| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/09/21 11:05 | flow | patch-triage |
3mArgs:null Results: {
"EnableConfigs": [
"VSOCKETS",
"VSOCKETS_LOOPBACK",
"VIRTIO_VSOCKETS"
],
"FocusSymbols": [
"vsock_connectible_sendmsg",
"virtio_transport_seqpacket_max_size"
],
"KMSANReasoning": "The patch introduces flow-control improvements for SOCK_SEQPACKET in AF_VSOCK (virtio transport). Specifically, it ensures that SEQPACKET messages wait until sufficient space is available (min_space = len - total_written) before enqueueing, and rejects oversized messages up-front via a new transport callback (`seqpacket_max_size`).\n\nNo uninitialized memory hazards are introduced or exposed:\n1. All newly introduced local variables (`min_space`, `max_size`) are deterministically initialized in all execution branches prior to being read.\n2. No data is copied to user space; the modified path is in the send/transmit path (`vsock_connectible_sendmsg`), moving data from user space into socket buffers.\n3. No kernel heap/stack buffers or structure paddings that could be read or leaked are modified or allocated.\n4. Surrounding buffer bounds and data access logic remain strictly bounded by user-supplied lengths.\n\nAny potential issues arising from this patch (such as deadlocks, lock contention around `tx_lock`, or socket reference handling) fall entirely under LOCKDEP, KASAN, or standard kernel bug detection mechanisms. Thus, a dedicated KMSAN fuzzing session is not justified.",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies the send path for AF_VSOCK SOCK_SEQPACKET sockets in vsock_connectible_sendmsg() to ensure atomicity by requiring enough buffer space for the entire message before enqueueing, and introduces an up-front message size check via the new transport callback seqpacket_max_size (implemented as virtio_transport_seqpacket_max_size for virtio and loopback transports). This reachable core networking socket path alters blocking wait semantics, signal handling, and error handling, making it an ideal target for fuzzing.",
"WorthFuzzing": true
} |
| 1/1 | 2026/09/21 11:05 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 7c72772b3ffb160ac7c2ef59de999c2e584034f8\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Sep 21 11:05:49 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h\nindex f91704731057e..e96790c038963 100644\n--- a/include/linux/virtio_vsock.h\n+++ b/include/linux/virtio_vsock.h\n@@ -219,6 +219,7 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,\n s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);\n s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);\n u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk);\n+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk);\n \n ssize_t virtio_transport_unsent_bytes(struct vsock_sock *vsk);\n \ndiff --git a/include/net/af_vsock.h b/include/net/af_vsock.h\nindex 5549298c1ec6b..d94c613ef604b 100644\n--- a/include/net/af_vsock.h\n+++ b/include/net/af_vsock.h\n@@ -143,6 +143,7 @@ struct vsock_transport {\n \t\t\t\t size_t len);\n \tbool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);\n \tu32 (*seqpacket_has_data)(struct vsock_sock *vsk);\n+\tu32 (*seqpacket_max_size)(struct vsock_sock *vsk);\n \n \t/* Notification. */\n \tint (*notify_poll_in)(struct vsock_sock *, size_t, bool *);\ndiff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c\nindex f840498b58afb..ac64cb9571643 100644\n--- a/net/vmw_vsock/af_vsock.c\n+++ b/net/vmw_vsock/af_vsock.c\n@@ -2250,9 +2250,32 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\n \n \twhile (total_written \u003c len) {\n \t\tssize_t written;\n+\t\ts64 min_space;\n+\n+\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\n+\t\t\t/* A SEQPACKET message must be delivered atomically, so\n+\t\t\t * wait until the whole remaining message fits before\n+\t\t\t * enqueuing. Otherwise a credit-limited partial send that\n+\t\t\t * later errors out (e.g. -EINTR) leaves EOM-less fragments\n+\t\t\t * that the peer merges into the next message.\n+\t\t\t *\n+\t\t\t * Reject a message that can never fit up front so the wait\n+\t\t\t * below cannot block forever (a peer may advertise a small\n+\t\t\t * buf_alloc); this mirrors the -EMSGSIZE the transport\n+\t\t\t * returns for an oversized message.\n+\t\t\t */\n+\t\t\tif (transport-\u003eseqpacket_max_size \u0026\u0026\n+\t\t\t len \u003e transport-\u003eseqpacket_max_size(vsk)) {\n+\t\t\t\terr = -EMSGSIZE;\n+\t\t\t\tgoto out_err;\n+\t\t\t}\n+\t\t\tmin_space = len - total_written;\n+\t\t} else {\n+\t\t\tmin_space = 1;\n+\t\t}\n \n \t\tadd_wait_queue(sk_sleep(sk), \u0026wait);\n-\t\twhile (vsock_stream_has_space(vsk) == 0 \u0026\u0026\n+\t\twhile (vsock_stream_has_space(vsk) \u003c min_space \u0026\u0026\n \t\t sk-\u003esk_err == 0 \u0026\u0026\n \t\t !(sk-\u003esk_shutdown \u0026 SEND_SHUTDOWN) \u0026\u0026\n \t\t !(vsk-\u003epeer_shutdown \u0026 RCV_SHUTDOWN)) {\ndiff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c\nindex 4f9aa9c4c3aa5..b7d587a202044 100644\n--- a/net/vmw_vsock/virtio_transport.c\n+++ b/net/vmw_vsock/virtio_transport.c\n@@ -585,6 +585,7 @@ static struct virtio_transport virtio_transport = {\n \t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\n \t\t.seqpacket_allow = virtio_transport_seqpacket_allow,\n \t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n+\t\t.seqpacket_max_size = virtio_transport_seqpacket_max_size,\n \n \t\t.msgzerocopy_allow = virtio_transport_msgzerocopy_allow,\n \ndiff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c\nindex f225f53ed4bab..e10e7b95807e3 100644\n--- a/net/vmw_vsock/virtio_transport_common.c\n+++ b/net/vmw_vsock/virtio_transport_common.c\n@@ -994,6 +994,19 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\n }\n EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);\n \n+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)\n+{\n+\tstruct virtio_vsock_sock *vvs = vsk-\u003etrans;\n+\tu32 max_size;\n+\n+\tspin_lock_bh(\u0026vvs-\u003etx_lock);\n+\tmax_size = virtio_transport_tx_buf_size(vvs);\n+\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n+\n+\treturn max_size;\n+}\n+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_max_size);\n+\n int\n virtio_transport_dgram_dequeue(struct vsock_sock *vsk,\n \t\t\t struct msghdr *msg,\ndiff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c\nindex 8068d1b6e8518..b9a0cc861d495 100644\n--- a/net/vmw_vsock/vsock_loopback.c\n+++ b/net/vmw_vsock/vsock_loopback.c\n@@ -90,6 +90,7 @@ static struct virtio_transport loopback_transport = {\n \t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\n \t\t.seqpacket_allow = vsock_loopback_seqpacket_allow,\n \t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n+\t\t.seqpacket_max_size = virtio_transport_seqpacket_max_size,\n \n \t\t.msgzerocopy_allow = vsock_loopback_msgzerocopy_allow,\n \n"
} |
| 2/1 | 2026/09/21 11:05 | agent | patch-evaluator |
1mModel:core Args: null Results: {
"EnableConfigs": [
"VSOCKETS",
"VSOCKETS_LOOPBACK",
"VIRTIO_VSOCKETS"
],
"FocusSymbols": [
"vsock_connectible_sendmsg",
"virtio_transport_seqpacket_max_size"
],
"Reasoning": "The patch modifies the send path for AF_VSOCK SOCK_SEQPACKET sockets in vsock_connectible_sendmsg() to ensure atomicity by requiring enough buffer space for the entire message before enqueueing, and introduces an up-front message size check via the new transport callback seqpacket_max_size (implemented as virtio_transport_seqpacket_max_size for virtio and loopback transports). This reachable core networking socket path alters blocking wait semantics, signal handling, and error handling, making it an ideal target for fuzzing.",
"WorthFuzzing": true
}Instruction: You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.
IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.
================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.
- REACHABILITY IS THE PRIMARY GATE:
Fuzzing can only discover bugs in code that can actually execute in standard virtualized
environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
regardless of whether it adds assertions or complex logic.
- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
Patch authors routinely label changes as "cleanups", "refactorings", or state
"No functional change intended". Do NOT take these claims at face value.
Code refactorings that rearrange logic, introduce helper functions, or alter state management
in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
If reachable executable code is modified or refactored, it MUST be fuzzed.
- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
Even if the author believes the invariant always holds, fuzzing is essential to verify whether
an unusual sequence of operations can violate it.
================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:
- Non-kernel and non-executable changes:
* Modifications to Documentation/, comments, or spelling fixes.
* User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
that do not affect the compiled kernel image (vmlinux) or kernel modules.
* Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
that do not alter control flow or data structures.
* Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
* Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
* Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
physical PCI hot-unplug or manual sysfs driver unbinding.
* Code paths exclusive to architectures other than the target architecture.
================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
* Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
* Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
* Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
* Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).
================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:
- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
Do NOT list generic, ubiquitous functions called by almost every program in the corpus
(including, but not limited to: general memory allocators and deallocators, page fault
and trap handlers, or core synchronization primitives; this is not an exhaustive list).
Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
which severely dilutes fuzzing effort away from the actual changes.
- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
List functions that specifically implement the logic being added or altered, or direct API entrypoints
for the subsystem feature under review.
- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).
================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt: Target architecture: amd64
For your convenience, here is the diff of the changes:
commit 7c72772b3ffb160ac7c2ef59de999c2e584034f8
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Sep 21 11:05:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index f91704731057e..e96790c038963 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -219,6 +219,7 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk);
+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk);
ssize_t virtio_transport_unsent_bytes(struct vsock_sock *vsk);
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 5549298c1ec6b..d94c613ef604b 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -143,6 +143,7 @@ struct vsock_transport {
size_t len);
bool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);
u32 (*seqpacket_has_data)(struct vsock_sock *vsk);
+ u32 (*seqpacket_max_size)(struct vsock_sock *vsk);
/* Notification. */
int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index f840498b58afb..ac64cb9571643 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2250,9 +2250,32 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
while (total_written < len) {
ssize_t written;
+ s64 min_space;
+
+ if (sk->sk_type == SOCK_SEQPACKET) {
+ /* A SEQPACKET message must be delivered atomically, so
+ * wait until the whole remaining message fits before
+ * enqueuing. Otherwise a credit-limited partial send that
+ * later errors out (e.g. -EINTR) leaves EOM-less fragments
+ * that the peer merges into the next message.
+ *
+ * Reject a message that can never fit up front so the wait
+ * below cannot block forever (a peer may advertise a small
+ * buf_alloc); this mirrors the -EMSGSIZE the transport
+ * returns for an oversized message.
+ */
+ if (transport->seqpacket_max_size &&
+ len > transport->seqpacket_max_size(vsk)) {
+ err = -EMSGSIZE;
+ goto out_err;
+ }
+ min_space = len - total_written;
+ } else {
+ min_space = 1;
+ }
add_wait_queue(sk_sleep(sk), &wait);
- while (vsock_stream_has_space(vsk) == 0 &&
+ while (vsock_stream_has_space(vsk) < min_space &&
sk->sk_err == 0 &&
!(sk->sk_shutdown & SEND_SHUTDOWN) &&
!(vsk->peer_shutdown & RCV_SHUTDOWN)) {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 4f9aa9c4c3aa5..b7d587a202044 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -585,6 +585,7 @@ static struct virtio_transport virtio_transport = {
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = virtio_transport_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
+ .seqpacket_max_size = virtio_transport_seqpacket_max_size,
.msgzerocopy_allow = virtio_transport_msgzerocopy_allow,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index f225f53ed4bab..e10e7b95807e3 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -994,6 +994,19 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
}
EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ u32 max_size;
+
+ spin_lock_bh(&vvs->tx_lock);
+ max_size = virtio_transport_tx_buf_size(vvs);
+ spin_unlock_bh(&vvs->tx_lock);
+
+ return max_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_max_size);
+
int
virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 8068d1b6e8518..b9a0cc861d495 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -90,6 +90,7 @@ static struct virtio_transport loopback_transport = {
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = vsock_loopback_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
+ .seqpacket_max_size = virtio_transport_seqpacket_max_size,
.msgzerocopy_allow = vsock_loopback_msgzerocopy_allow,
|
| 3/2 | 2026/09/21 11:05 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 4547 output: 20 thoughts: 744 Thoughts: **Analyzing the Proposed vsock Patch** Okay, let's dive into this patch. My initial assessment is that it targets the vsock subsystem, specifically touching the virtio-vsock implementation, and I need to understand the implications of these changes, which seem to be primarily focused on SEQPACKET sockets. The diff impacts several key files: `virtio_vsock.h`, `af_vsock.h`, and core implementation files in `net/vmw_vsock/`, namely `af_vsock.c`, `virtio_transport.c`, `virtio_transport_common.c`, and `vsock_loopback.c`. This suggests a potentially widespread change, probably related to the transport layer. Looking at `af_vsock.c`, the `vsock_connectible_sendmsg` function has a critical modification. It looks like it's introducing logic to handle the atomicity requirement of `SOCK_SEQPACKET`. The code now calculates `min_space` and uses it in `vsock_stream_has_space`. A crucial addition is a check for `transport->seqpacket_max_size` to prevent issues with partial sends that would violate the atomic nature of the packets. This is good; it's explicitly handling the `EMSGSIZE` condition, too. The introduction of `virtio_transport_seqpacket_max_size` function suggests that the transport layer needs to provide the maximum size. The `virtio_transport_common.c` file provides an implementation for calculating the maximum size for SEQPACKET, which looks to be using a spinlock to protect the `tx_buf_size`. Fine; this is the expected mechanism for getting the tx buffer size in the virtio transport layer, and it's exposed for other transports. The patch seems to be setting `.seqpacket_max_size` in the `virtio_transport.c` and `vsock_loopback.c` files. This is consistent. However, given my experience, I need to check whether other transports are using/implementing the new functionality. Specifically, I should check whether `vhost/vsock.c` or any other transport has implemented the new function. I can use my `grepper` tool to search the code base for other vsock transports. This is crucial for verifying that the new functionalities don't create problems on other vsock implementations. |
| 4/2 | 2026/09/21 11:06 | tool | grepper |
0mArgs:{
"Expression": "struct vsock_transport "
}Results: {
"Output": "include/linux/virtio_vsock.h=184=struct virtio_transport {\ninclude/linux/virtio_vsock.h-185-\t/* This must be the first field */\ninclude/linux/virtio_vsock.h:186:\tstruct vsock_transport transport;\ninclude/linux/virtio_vsock.h-187-\n--\ninclude/net/af_vsock.h=29=struct vsock_sock {\n--\ninclude/net/af_vsock.h-31-\tstruct sock sk;\ninclude/net/af_vsock.h:32:\tconst struct vsock_transport *transport;\ninclude/net/af_vsock.h-33-\tstruct sockaddr_vm local_addr;\n--\ninclude/net/af_vsock.h=90=struct vsock_transport_send_notify_data {\n--\ninclude/net/af_vsock.h-104-\ninclude/net/af_vsock.h:105:struct vsock_transport {\ninclude/net/af_vsock.h-106-\tstruct module *module;\n--\ninclude/net/af_vsock.h-197-\ninclude/net/af_vsock.h:198:int vsock_core_register(const struct vsock_transport *t, int features);\ninclude/net/af_vsock.h:199:void vsock_core_unregister(const struct vsock_transport *t);\ninclude/net/af_vsock.h-200-\ninclude/net/af_vsock.h-201-/* The transport may downcast this to access transport-specific functions */\ninclude/net/af_vsock.h:202:const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk);\ninclude/net/af_vsock.h-203-\n--\ninclude/net/af_vsock.h=233=bool vsock_check_source(const struct vsock_sock *vsk,\ninclude/net/af_vsock.h:234:\t\t\tconst struct vsock_transport *transport,\ninclude/net/af_vsock.h-235-\t\t\tconst struct sockaddr_vm *src);\ninclude/net/af_vsock.h=236=void vsock_remove_sock(struct vsock_sock *vsk);\ninclude/net/af_vsock.h:237:void vsock_for_each_connected_socket(struct vsock_transport *transport,\ninclude/net/af_vsock.h-238-\t\t\t\t void (*fn)(struct sock *sk));\n--\ninclude/net/af_vsock.h=268=static inline void __init vsock_bpf_build_proto(void)\n--\ninclude/net/af_vsock.h-271-\ninclude/net/af_vsock.h:272:static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)\ninclude/net/af_vsock.h-273-{\n--\nnet/vmw_vsock/af_vsock.c=182=struct proto vsock_proto = {\n--\nnet/vmw_vsock/af_vsock.c-201-/* Transport used for host-\u003eguest communication */\nnet/vmw_vsock/af_vsock.c:202:static const struct vsock_transport *transport_h2g;\nnet/vmw_vsock/af_vsock.c-203-/* Transport used for guest-\u003ehost communication */\nnet/vmw_vsock/af_vsock.c:204:static const struct vsock_transport *transport_g2h;\nnet/vmw_vsock/af_vsock.c-205-/* Transport used for DGRAM communication */\nnet/vmw_vsock/af_vsock.c:206:static const struct vsock_transport *transport_dgram;\nnet/vmw_vsock/af_vsock.c-207-/* Transport used for local communication */\nnet/vmw_vsock/af_vsock.c:208:static const struct vsock_transport *transport_local;\nnet/vmw_vsock/af_vsock.c-209-static DEFINE_MUTEX(vsock_register_mutex);\n--\nnet/vmw_vsock/af_vsock.c=456=bool vsock_check_source(const struct vsock_sock *vsk,\nnet/vmw_vsock/af_vsock.c:457:\t\t\tconst struct vsock_transport *transport,\nnet/vmw_vsock/af_vsock.c-458-\t\t\tconst struct sockaddr_vm *src)\n--\nnet/vmw_vsock/af_vsock.c=481=EXPORT_SYMBOL_GPL(vsock_remove_sock);\nnet/vmw_vsock/af_vsock.c-482-\nnet/vmw_vsock/af_vsock.c:483:void vsock_for_each_connected_socket(struct vsock_transport *transport,\nnet/vmw_vsock/af_vsock.c-484-\t\t\t\t void (*fn)(struct sock *sk))\n--\nnet/vmw_vsock/af_vsock.c=599=int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)\nnet/vmw_vsock/af_vsock.c-600-{\nnet/vmw_vsock/af_vsock.c:601:\tconst struct vsock_transport *new_transport;\nnet/vmw_vsock/af_vsock.c-602-\tstruct sock *sk = sk_vsock(vsk);\n--\nnet/vmw_vsock/af_vsock.c=712=EXPORT_SYMBOL_GPL(vsock_assign_transport);\n--\nnet/vmw_vsock/af_vsock.c-717- */\nnet/vmw_vsock/af_vsock.c:718:static u32 vsock_registered_transport_cid(const struct vsock_transport **transport)\nnet/vmw_vsock/af_vsock.c-719-{\n--\nnet/vmw_vsock/af_vsock.c=1302=static __poll_t vsock_poll(struct file *file, struct socket *sock,\n--\nnet/vmw_vsock/af_vsock.c-1342-\t} else if (sock_type_connectible(sk-\u003esk_type)) {\nnet/vmw_vsock/af_vsock.c:1343:\t\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-1344-\t\tu32 peer_shutdown;\n--\nnet/vmw_vsock/af_vsock.c=1429=static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-1435-\tstruct sockaddr_vm *remote_addr;\nnet/vmw_vsock/af_vsock.c:1436:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-1437-\n--\nnet/vmw_vsock/af_vsock.c=1672=static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-1673-{\nnet/vmw_vsock/af_vsock.c:1674:\tconst struct vsock_transport *transport = vsk-\u003etransport;\nnet/vmw_vsock/af_vsock.c-1675-\n--\nnet/vmw_vsock/af_vsock.c=1704=static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\n--\nnet/vmw_vsock/af_vsock.c-1709-\tstruct vsock_sock *vsk;\nnet/vmw_vsock/af_vsock.c:1710:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-1711-\tstruct sockaddr_vm *remote_addr;\n--\nnet/vmw_vsock/af_vsock.c=1998=static void vsock_update_buffer_size(struct vsock_sock *vsk,\nnet/vmw_vsock/af_vsock.c:1999:\t\t\t\t const struct vsock_transport *transport,\nnet/vmw_vsock/af_vsock.c-2000-\t\t\t\t u64 val)\n--\nnet/vmw_vsock/af_vsock.c=2015=static int vsock_connectible_setsockopt(struct socket *sock,\n--\nnet/vmw_vsock/af_vsock.c-2023-\tstruct vsock_sock *vsk;\nnet/vmw_vsock/af_vsock.c:2024:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2025-\tu64 val;\n--\nnet/vmw_vsock/af_vsock.c=2188=static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2192-\tstruct vsock_sock *vsk;\nnet/vmw_vsock/af_vsock.c:2193:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2194-\tssize_t total_written;\n--\nnet/vmw_vsock/af_vsock.c=2373=static int vsock_connectible_wait_data(struct sock *sk,\n--\nnet/vmw_vsock/af_vsock.c-2378-{\nnet/vmw_vsock/af_vsock.c:2379:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2380-\tstruct vsock_sock *vsk;\n--\nnet/vmw_vsock/af_vsock.c=2440=static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2443-\tstruct vsock_transport_recv_notify_data recv_data;\nnet/vmw_vsock/af_vsock.c:2444:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2445-\tstruct vsock_sock *vsk;\n--\nnet/vmw_vsock/af_vsock.c=2519=static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2521-{\nnet/vmw_vsock/af_vsock.c:2522:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2523-\tstruct vsock_sock *vsk;\n--\nnet/vmw_vsock/af_vsock.c=2570=__vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,\n--\nnet/vmw_vsock/af_vsock.c-2574-\tstruct vsock_sock *vsk;\nnet/vmw_vsock/af_vsock.c:2575:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2576-\tint err;\n--\nnet/vmw_vsock/af_vsock.c=2653=static int vsock_set_rcvlowat(struct sock *sk, int val)\nnet/vmw_vsock/af_vsock.c-2654-{\nnet/vmw_vsock/af_vsock.c:2655:\tconst struct vsock_transport *transport;\nnet/vmw_vsock/af_vsock.c-2656-\tstruct vsock_sock *vsk;\n--\nnet/vmw_vsock/af_vsock.c=3090=static void __exit vsock_exit(void)\n--\nnet/vmw_vsock/af_vsock.c-3097-\nnet/vmw_vsock/af_vsock.c:3098:const struct vsock_transport *vsock_core_get_transport(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-3099-{\n--\nnet/vmw_vsock/af_vsock.c=3102=EXPORT_SYMBOL_GPL(vsock_core_get_transport);\nnet/vmw_vsock/af_vsock.c-3103-\nnet/vmw_vsock/af_vsock.c:3104:int vsock_core_register(const struct vsock_transport *t, int features)\nnet/vmw_vsock/af_vsock.c-3105-{\nnet/vmw_vsock/af_vsock.c:3106:\tconst struct vsock_transport *t_h2g, *t_g2h, *t_dgram, *t_local;\nnet/vmw_vsock/af_vsock.c-3107-\tint err = mutex_lock_interruptible(\u0026vsock_register_mutex);\n--\nnet/vmw_vsock/af_vsock.c=3158=EXPORT_SYMBOL_GPL(vsock_core_register);\nnet/vmw_vsock/af_vsock.c-3159-\nnet/vmw_vsock/af_vsock.c:3160:void vsock_core_unregister(const struct vsock_transport *t)\nnet/vmw_vsock/af_vsock.c-3161-{\n--\nnet/vmw_vsock/hyperv_transport.c=857=int hvs_notify_set_rcvlowat(struct vsock_sock *vsk, int val)\n--\nnet/vmw_vsock/hyperv_transport.c-861-\nnet/vmw_vsock/hyperv_transport.c:862:static struct vsock_transport hvs_transport = {\nnet/vmw_vsock/hyperv_transport.c-863-\t.module = THIS_MODULE,\n--\nnet/vmw_vsock/virtio_transport_common.c=41=virtio_transport_get_ops(struct vsock_sock *vsk)\nnet/vmw_vsock/virtio_transport_common.c-42-{\nnet/vmw_vsock/virtio_transport_common.c:43:\tconst struct vsock_transport *t = vsock_core_get_transport(vsk);\nnet/vmw_vsock/virtio_transport_common.c-44-\n--\nnet/vmw_vsock/vmci_transport.c=76=static int PROTOCOL_OVERRIDE = -1;\nnet/vmw_vsock/vmci_transport.c-77-\nnet/vmw_vsock/vmci_transport.c:78:static struct vsock_transport vmci_transport; /* forward declaration */\nnet/vmw_vsock/vmci_transport.c-79-\n--\nnet/vmw_vsock/vmci_transport.c=2065=static u32 vmci_transport_get_local_cid(void)\n--\nnet/vmw_vsock/vmci_transport.c-2069-\nnet/vmw_vsock/vmci_transport.c:2070:static struct vsock_transport vmci_transport = {\nnet/vmw_vsock/vmci_transport.c-2071-\t.module = THIS_MODULE,\n"
} |
| 5/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 9907 output: 18 thoughts: 20 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Investigating Sequence Packet Socket Support** Okay, so we need to expand our search criteria. I'm thinking we should broaden the scope of our analysis and specifically grep for any instances related to `seqpacket_allow`. This suggests a potential focus on socket options or configuration flags that explicitly enable or regulate sequence packet (SEQPACKET) communication. Furthermore, I'm going to extend the search to include other transports known to utilize or be compatible with the SEQPACKET socket type. This should give us a more complete picture of its usage throughout the codebase, rather than limiting ourselves to a single keyword. By looking at related transports, we might uncover some interesting implementation choices or workarounds. |
| 6/2 | 2026/09/21 11:06 | tool | grepper |
0mArgs:{
"Expression": "seqpacket_allow"
}Results: {
"Output": "drivers/vhost/vsock.c=48=struct vhost_vsock {\n--\ndrivers/vhost/vsock.c-62-\tu32 guest_cid;\ndrivers/vhost/vsock.c:63:\tbool seqpacket_allow;\ndrivers/vhost/vsock.c-64-};\n--\ndrivers/vhost/vsock.c=436=static bool vhost_transport_msgzerocopy_allow(void)\n--\ndrivers/vhost/vsock.c-440-\ndrivers/vhost/vsock.c:441:static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk,\ndrivers/vhost/vsock.c-442-\t\t\t\t\t u32 remote_cid);\n--\ndrivers/vhost/vsock.c=450=static struct virtio_transport vhost_transport = {\n--\ndrivers/vhost/vsock.c-478-\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\ndrivers/vhost/vsock.c:479:\t\t.seqpacket_allow = vhost_transport_seqpacket_allow,\ndrivers/vhost/vsock.c-480-\t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n--\ndrivers/vhost/vsock.c-504-\ndrivers/vhost/vsock.c:505:static bool vhost_transport_seqpacket_allow(struct vsock_sock *vsk,\ndrivers/vhost/vsock.c-506-\t\t\t\t\t u32 remote_cid)\n--\ndrivers/vhost/vsock.c-509-\tstruct vhost_vsock *vsock;\ndrivers/vhost/vsock.c:510:\tbool seqpacket_allow = false;\ndrivers/vhost/vsock.c-511-\n--\ndrivers/vhost/vsock.c-515-\tif (vsock)\ndrivers/vhost/vsock.c:516:\t\tseqpacket_allow = vsock-\u003eseqpacket_allow;\ndrivers/vhost/vsock.c-517-\n--\ndrivers/vhost/vsock.c-519-\ndrivers/vhost/vsock.c:520:\treturn seqpacket_allow;\ndrivers/vhost/vsock.c-521-}\n--\ndrivers/vhost/vsock.c=698=static int vhost_vsock_dev_open(struct inode *inode, struct file *file)\n--\ndrivers/vhost/vsock.c-721-\tvsock-\u003eguest_cid = 0; /* no CID assigned yet */\ndrivers/vhost/vsock.c:722:\tvsock-\u003eseqpacket_allow = false;\ndrivers/vhost/vsock.c-723-\n--\ndrivers/vhost/vsock.c=854=static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)\n--\ndrivers/vhost/vsock.c-874-\ndrivers/vhost/vsock.c:875:\tvsock-\u003eseqpacket_allow = features \u0026 (1ULL \u003c\u003c VIRTIO_VSOCK_F_SEQPACKET);\ndrivers/vhost/vsock.c-876-\n--\ninclude/net/af_vsock.h=105=struct vsock_transport {\n--\ninclude/net/af_vsock.h-143-\t\t\t\t size_t len);\ninclude/net/af_vsock.h:144:\tbool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);\ninclude/net/af_vsock.h-145-\tu32 (*seqpacket_has_data)(struct vsock_sock *vsk);\n--\nnet/vmw_vsock/af_vsock.c=599=int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)\n--\nnet/vmw_vsock/af_vsock.c-691-\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\nnet/vmw_vsock/af_vsock.c:692:\t\tif (!new_transport-\u003eseqpacket_allow ||\nnet/vmw_vsock/af_vsock.c:693:\t\t !new_transport-\u003eseqpacket_allow(vsk, remote_cid)) {\nnet/vmw_vsock/af_vsock.c-694-\t\t\tmodule_put(new_transport-\u003emodule);\n--\nnet/vmw_vsock/virtio_transport.c=30=struct virtio_vsock {\n--\nnet/vmw_vsock/virtio_transport.c-58-\tu32 guest_cid;\nnet/vmw_vsock/virtio_transport.c:59:\tbool seqpacket_allow;\nnet/vmw_vsock/virtio_transport.c-60-\n--\nnet/vmw_vsock/virtio_transport.c=543=bool virtio_transport_stream_allow(struct vsock_sock *vsk, u32 cid, u32 port)\n--\nnet/vmw_vsock/virtio_transport.c-547-\nnet/vmw_vsock/virtio_transport.c:548:static bool virtio_transport_seqpacket_allow(struct vsock_sock *vsk,\nnet/vmw_vsock/virtio_transport.c-549-\t\t\t\t\t u32 remote_cid);\n--\nnet/vmw_vsock/virtio_transport.c=557=static struct virtio_transport virtio_transport = {\n--\nnet/vmw_vsock/virtio_transport.c-585-\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/virtio_transport.c:586:\t\t.seqpacket_allow = virtio_transport_seqpacket_allow,\nnet/vmw_vsock/virtio_transport.c-587-\t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n--\nnet/vmw_vsock/virtio_transport.c=614=static bool\nnet/vmw_vsock/virtio_transport.c:615:virtio_transport_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid)\nnet/vmw_vsock/virtio_transport.c-616-{\nnet/vmw_vsock/virtio_transport.c-617-\tstruct virtio_vsock *vsock;\nnet/vmw_vsock/virtio_transport.c:618:\tbool seqpacket_allow;\nnet/vmw_vsock/virtio_transport.c-619-\n--\nnet/vmw_vsock/virtio_transport.c-622-\nnet/vmw_vsock/virtio_transport.c:623:\tseqpacket_allow = false;\nnet/vmw_vsock/virtio_transport.c-624-\trcu_read_lock();\n--\nnet/vmw_vsock/virtio_transport.c-626-\tif (vsock)\nnet/vmw_vsock/virtio_transport.c:627:\t\tseqpacket_allow = vsock-\u003eseqpacket_allow;\nnet/vmw_vsock/virtio_transport.c-628-\trcu_read_unlock();\nnet/vmw_vsock/virtio_transport.c-629-\nnet/vmw_vsock/virtio_transport.c:630:\treturn seqpacket_allow;\nnet/vmw_vsock/virtio_transport.c-631-}\n--\nnet/vmw_vsock/virtio_transport.c=801=static int virtio_vsock_probe(struct virtio_device *vdev)\n--\nnet/vmw_vsock/virtio_transport.c-836-\tif (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))\nnet/vmw_vsock/virtio_transport.c:837:\t\tvsock-\u003eseqpacket_allow = true;\nnet/vmw_vsock/virtio_transport.c-838-\n--\nnet/vmw_vsock/vsock_loopback.c=40=static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/vsock_loopback.c-48-\nnet/vmw_vsock/vsock_loopback.c:49:static bool vsock_loopback_seqpacket_allow(struct vsock_sock *vsk,\nnet/vmw_vsock/vsock_loopback.c-50-\t\t\t\t\t u32 remote_cid);\n--\nnet/vmw_vsock/vsock_loopback.c=63=static struct virtio_transport loopback_transport = {\n--\nnet/vmw_vsock/vsock_loopback.c-90-\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/vsock_loopback.c:91:\t\t.seqpacket_allow = vsock_loopback_seqpacket_allow,\nnet/vmw_vsock/vsock_loopback.c-92-\t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n--\nnet/vmw_vsock/vsock_loopback.c=118=static bool\nnet/vmw_vsock/vsock_loopback.c:119:vsock_loopback_seqpacket_allow(struct vsock_sock *vsk, u32 remote_cid)\nnet/vmw_vsock/vsock_loopback.c-120-{\n"
} |
| 7/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 12586 output: 43 thoughts: 352 Thoughts: **Analyzing vsock Seqpacket Handling**
Okay, hold on a second! I need to dig into this. My initial thought is to check `drivers/vhost/vsock.c`. Does it actually support seqpacket, but somehow neglect to implement `.seqpacket_max_size`? That feels like a potential oversight. Looking at the code:
```c
static struct virtio_transport vhost_transport = {
...
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = vhost_transport_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
```
I see the callbacks are there, so it *should* support it. Hold on, did the recent patch touch `drivers/vhost/vsock.c`? No! That's interesting.
Now, let's pivot to `af_vsock.c`. I see:
```c
if (transport->seqpacket_max_size &&
len > transport->seqpacket_max_size(vsk)) {
err = -EMSGSIZE;
goto out_err;
}
min_space = len - total_written;
```
Aha! If `transport->seqpacket_max_size` is NULL, the initial size check with the `EMSGSIZE` error is skipped. But `min_space` is *still* calculated as `len - total_written`. This means there's a potential vulnerability there! And further, if `vsock_stream_has_space(vsk) < min_space`... the connection could be vulnerable!
I'm getting a clearer picture. To get the whole picture, let me look at `net/vmw_vsock/af_vsock.c` around line 2250 to get the complete context of `vsock_connectible_sendmsg`. That should give me the full picture.
|
| 8/2 | 2026/09/21 11:06 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/af_vsock.c",
"FirstLine": 2240,
"LineCount": 80
}Results: {
"Contents": "2240:\t\t\terr = -EOPNOTSUPP;\n2241:\t\t\tgoto out;\n2242:\t\t}\n2243:\t\n2244:\t\t/* Wait for room in the produce queue to enqueue our user's data. */\n2245:\t\ttimeout = sock_sndtimeo(sk, msg-\u003emsg_flags \u0026 MSG_DONTWAIT);\n2246:\t\n2247:\t\terr = transport-\u003enotify_send_init(vsk, \u0026send_data);\n2248:\t\tif (err \u003c 0)\n2249:\t\t\tgoto out;\n2250:\t\n2251:\t\twhile (total_written \u003c len) {\n2252:\t\t\tssize_t written;\n2253:\t\t\ts64 min_space;\n2254:\t\n2255:\t\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\n2256:\t\t\t\t/* A SEQPACKET message must be delivered atomically, so\n2257:\t\t\t\t * wait until the whole remaining message fits before\n2258:\t\t\t\t * enqueuing. Otherwise a credit-limited partial send that\n2259:\t\t\t\t * later errors out (e.g. -EINTR) leaves EOM-less fragments\n2260:\t\t\t\t * that the peer merges into the next message.\n2261:\t\t\t\t *\n2262:\t\t\t\t * Reject a message that can never fit up front so the wait\n2263:\t\t\t\t * below cannot block forever (a peer may advertise a small\n2264:\t\t\t\t * buf_alloc); this mirrors the -EMSGSIZE the transport\n2265:\t\t\t\t * returns for an oversized message.\n2266:\t\t\t\t */\n2267:\t\t\t\tif (transport-\u003eseqpacket_max_size \u0026\u0026\n2268:\t\t\t\t len \u003e transport-\u003eseqpacket_max_size(vsk)) {\n2269:\t\t\t\t\terr = -EMSGSIZE;\n2270:\t\t\t\t\tgoto out_err;\n2271:\t\t\t\t}\n2272:\t\t\t\tmin_space = len - total_written;\n2273:\t\t\t} else {\n2274:\t\t\t\tmin_space = 1;\n2275:\t\t\t}\n2276:\t\n2277:\t\t\tadd_wait_queue(sk_sleep(sk), \u0026wait);\n2278:\t\t\twhile (vsock_stream_has_space(vsk) \u003c min_space \u0026\u0026\n2279:\t\t\t sk-\u003esk_err == 0 \u0026\u0026\n2280:\t\t\t !(sk-\u003esk_shutdown \u0026 SEND_SHUTDOWN) \u0026\u0026\n2281:\t\t\t !(vsk-\u003epeer_shutdown \u0026 RCV_SHUTDOWN)) {\n2282:\t\n2283:\t\t\t\t/* Don't wait for non-blocking sockets. */\n2284:\t\t\t\tif (timeout == 0) {\n2285:\t\t\t\t\terr = -EAGAIN;\n2286:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2287:\t\t\t\t\tgoto out_err;\n2288:\t\t\t\t}\n2289:\t\n2290:\t\t\t\terr = transport-\u003enotify_send_pre_block(vsk, \u0026send_data);\n2291:\t\t\t\tif (err \u003c 0) {\n2292:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2293:\t\t\t\t\tgoto out_err;\n2294:\t\t\t\t}\n2295:\t\n2296:\t\t\t\trelease_sock(sk);\n2297:\t\t\t\ttimeout = wait_woken(\u0026wait, TASK_INTERRUPTIBLE, timeout);\n2298:\t\t\t\tlock_sock(sk);\n2299:\t\t\t\tif (signal_pending(current)) {\n2300:\t\t\t\t\terr = sock_intr_errno(timeout);\n2301:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2302:\t\t\t\t\tgoto out_err;\n2303:\t\t\t\t} else if (timeout == 0) {\n2304:\t\t\t\t\terr = -EAGAIN;\n2305:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2306:\t\t\t\t\tgoto out_err;\n2307:\t\t\t\t}\n2308:\t\t\t}\n2309:\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2310:\t\n2311:\t\t\t/* These checks occur both as part of and after the loop\n2312:\t\t\t * conditional since we need to check before and after\n2313:\t\t\t * sleeping.\n2314:\t\t\t */\n2315:\t\t\tif (sk-\u003esk_err) {\n2316:\t\t\t\terr = -sk-\u003esk_err;\n2317:\t\t\t\tgoto out_err;\n2318:\t\t\t} else if ((sk-\u003esk_shutdown \u0026 SEND_SHUTDOWN) ||\n2319:\t\t\t\t (vsk-\u003epeer_shutdown \u0026 RCV_SHUTDOWN)) {\n"
} |
| 9/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 14665 output: 43 thoughts: 25 Thoughts: Okay, let's dive into this `vsock_connectible_sendmsg` function and see where we go next. I'll need to scroll down and examine the subsequent code flow to understand its progression. I expect to be able to understand the flow clearly and completely. |
| 10/2 | 2026/09/21 11:06 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/af_vsock.c",
"FirstLine": 2320,
"LineCount": 50
}Results: {
"Contents": "2320:\t\t\t\terr = -EPIPE;\n2321:\t\t\t\tgoto out_err;\n2322:\t\t\t}\n2323:\t\n2324:\t\t\terr = transport-\u003enotify_send_pre_enqueue(vsk, \u0026send_data);\n2325:\t\t\tif (err \u003c 0)\n2326:\t\t\t\tgoto out_err;\n2327:\t\n2328:\t\t\t/* Note that enqueue will only write as many bytes as are free\n2329:\t\t\t * in the produce queue, so we don't need to ensure len is\n2330:\t\t\t * smaller than the queue size. It is the caller's\n2331:\t\t\t * responsibility to check how many bytes we were able to send.\n2332:\t\t\t */\n2333:\t\n2334:\t\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\n2335:\t\t\t\twritten = transport-\u003eseqpacket_enqueue(vsk,\n2336:\t\t\t\t\t\t\tmsg, len - total_written);\n2337:\t\t\t} else {\n2338:\t\t\t\twritten = transport-\u003estream_enqueue(vsk,\n2339:\t\t\t\t\t\tmsg, len - total_written);\n2340:\t\t\t}\n2341:\t\n2342:\t\t\tif (written \u003c 0) {\n2343:\t\t\t\terr = written;\n2344:\t\t\t\tgoto out_err;\n2345:\t\t\t}\n2346:\t\n2347:\t\t\ttotal_written += written;\n2348:\t\n2349:\t\t\terr = transport-\u003enotify_send_post_enqueue(\n2350:\t\t\t\t\tvsk, written, \u0026send_data);\n2351:\t\t\tif (err \u003c 0)\n2352:\t\t\t\tgoto out_err;\n2353:\t\n2354:\t\t}\n2355:\t\n2356:\tout_err:\n2357:\t\tif (total_written \u003e 0) {\n2358:\t\t\t/* Return number of written bytes only if:\n2359:\t\t\t * 1) SOCK_STREAM socket.\n2360:\t\t\t * 2) SOCK_SEQPACKET socket when whole buffer is sent.\n2361:\t\t\t */\n2362:\t\t\tif (sk-\u003esk_type == SOCK_STREAM || total_written == len)\n2363:\t\t\t\terr = total_written;\n2364:\t\t}\n2365:\tout:\n2366:\t\tif (sk-\u003esk_type == SOCK_STREAM)\n2367:\t\t\terr = sk_stream_error(sk, msg-\u003emsg_flags, err);\n2368:\t\n2369:\t\trelease_sock(sk);\n"
} |
| 11/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 15486 output: 22 thoughts: 152 Thoughts: **AF_VSOCK Connection Discovery** Okay, here's an interesting tidbit! Digging into `af_vsock.c`, I see `vsock_connectible_sendmsg` is designed to manage both `SOCK_STREAM` and `SOCK_SEQPACKET` sockets within the AF_VSOCK family. Excellent! That confirms full AF_VSOCK support in the standard Linux kernel, which I already knew. And of course, QEMU's got virtio-vsock, with the loopback option readily available through the kernel module, right? Thinking about this, I recall that Syzkaller is actively fuzzing AF_VSOCK, and there are several interesting descriptions, such as `socket$vsock_stream` and `socket$vsock_seqpacket`, which are relevant to my current work. Given that, I think it's time to take a close look at `vsock_stream_has_space`. I'm curious to see how that function operates. |
| 12/2 | 2026/09/21 11:06 | tool | grepper |
0mArgs:{
"Expression": "vsock_stream_has_space"
}Results: {
"Output": "include/net/af_vsock.h=77=s64 vsock_stream_has_data(struct vsock_sock *vsk);\ninclude/net/af_vsock.h:78:s64 vsock_stream_has_space(struct vsock_sock *vsk);\ninclude/net/af_vsock.h-79-struct sock *vsock_create_connected(struct sock *parent);\n--\nnet/vmw_vsock/af_vsock.c=1104=EXPORT_SYMBOL_GPL(vsock_connectible_has_data);\nnet/vmw_vsock/af_vsock.c-1105-\nnet/vmw_vsock/af_vsock.c:1106:s64 vsock_stream_has_space(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-1107-{\n--\nnet/vmw_vsock/af_vsock.c-1112-}\nnet/vmw_vsock/af_vsock.c:1113:EXPORT_SYMBOL_GPL(vsock_stream_has_space);\nnet/vmw_vsock/af_vsock.c-1114-\n--\nnet/vmw_vsock/af_vsock.c=2188=static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2277-\t\tadd_wait_queue(sk_sleep(sk), \u0026wait);\nnet/vmw_vsock/af_vsock.c:2278:\t\twhile (vsock_stream_has_space(vsk) \u003c min_space \u0026\u0026\nnet/vmw_vsock/af_vsock.c-2279-\t\t sk-\u003esk_err == 0 \u0026\u0026\n--\nnet/vmw_vsock/virtio_transport_common.c=1130=virtio_transport_notify_poll_out(struct vsock_sock *vsk,\n--\nnet/vmw_vsock/virtio_transport_common.c-1135-\nnet/vmw_vsock/virtio_transport_common.c:1136:\tfree_space = vsock_stream_has_space(vsk);\nnet/vmw_vsock/virtio_transport_common.c-1137-\tif (free_space \u003e 0)\n--\nnet/vmw_vsock/vmci_transport_notify.c=362=vmci_transport_notify_pkt_poll_out(struct sock *sk,\n--\nnet/vmw_vsock/vmci_transport_notify.c-367-\nnet/vmw_vsock/vmci_transport_notify.c:368:\tproduce_q_free_space = vsock_stream_has_space(vsk);\nnet/vmw_vsock/vmci_transport_notify.c-369-\tif (produce_q_free_space \u003e 0) {\n--\nnet/vmw_vsock/vmci_transport_notify_qstate.c=180=vmci_transport_notify_pkt_poll_out(struct sock *sk,\n--\nnet/vmw_vsock/vmci_transport_notify_qstate.c-185-\nnet/vmw_vsock/vmci_transport_notify_qstate.c:186:\tproduce_q_free_space = vsock_stream_has_space(vsk);\nnet/vmw_vsock/vmci_transport_notify_qstate.c-187-\tif (produce_q_free_space \u003e 0) {\n"
} |
| 13/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 16797 output: 24 thoughts: 213 Thoughts: **Analyzing vsock_connectible_sendmsg and virtio_transport_seqpacket_max_size**
Okay, let's dive into this. I need to understand how these two functions are related, starting with `virtio_transport_seqpacket_max_size`. My initial thought is to figure out its purpose. The code snippet shows this:
```c
u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
u32 max_size;
spin_lock_bh(&vvs->tx_lock);
max_size = virtio_transport_tx_buf_size(vvs);
spin_unlock_bh(&vvs->tx_lock);
return max_size;
}
EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_max_size);
```
So, it retrieves `vsk->trans`, which is a `virtio_vsock_sock` pointer (`vvs`). It then calls `virtio_transport_tx_buf_size(vvs)` within a spinlock. Seems like the returned value is the maximum tx buffer size. The function is exported as GPL, so it's probably important for other modules. I need to find the definition of `virtio_transport_tx_buf_size` now. Let me grep for that function.
|
| 14/2 | 2026/09/21 11:06 | tool | grepper |
0mArgs:{
"Expression": "virtio_transport_tx_buf_size"
}Results: {
"Output": "net/vmw_vsock/virtio_transport_common.c=966=EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);\nnet/vmw_vsock/virtio_transport_common.c-967-\nnet/vmw_vsock/virtio_transport_common.c:968:static u32 virtio_transport_tx_buf_size(struct virtio_vsock_sock *vvs)\nnet/vmw_vsock/virtio_transport_common.c-969-{\n--\nnet/vmw_vsock/virtio_transport_common.c=978=virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\n--\nnet/vmw_vsock/virtio_transport_common.c-985-\nnet/vmw_vsock/virtio_transport_common.c:986:\tif (len \u003e virtio_transport_tx_buf_size(vvs)) {\nnet/vmw_vsock/virtio_transport_common.c-987-\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n--\nnet/vmw_vsock/virtio_transport_common.c=997=u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/virtio_transport_common.c-1002-\tspin_lock_bh(\u0026vvs-\u003etx_lock);\nnet/vmw_vsock/virtio_transport_common.c:1003:\tmax_size = virtio_transport_tx_buf_size(vvs);\nnet/vmw_vsock/virtio_transport_common.c-1004-\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n--\nnet/vmw_vsock/virtio_transport_common.c=1045=static s64 virtio_transport_has_space(struct virtio_vsock_sock *vvs)\n--\nnet/vmw_vsock/virtio_transport_common.c-1052-\t */\nnet/vmw_vsock/virtio_transport_common.c:1053:\tbytes = (s64)virtio_transport_tx_buf_size(vvs) -\nnet/vmw_vsock/virtio_transport_common.c-1054-\t\t(vvs-\u003etx_cnt - vvs-\u003epeer_fwd_cnt);\n"
} |
| 15/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 17977 output: 44 thoughts: 32 Thoughts: Okay, let's dive into this. I'm going to focus on lines 965-995 of `net/vmw_vsock/virtio_transport_common.c`. I need to get a clear picture of what's happening within that specific segment of the code. My experience tells me that these kinds of common transport modules are usually where the core communication and data handling functions reside. I'm expecting to see things related to data transfer, buffer management, error checking, and potentially, some crucial interaction with the underlying virtio layer. The goal is to quickly grasp the logical flow. I'll be looking for any key data structures being manipulated, the purpose of any loops or conditional statements, and especially any function calls that might signal involvement with other parts of the system – like the network stack, or the virtio device. Specifically I'm hoping to quickly identify the process that occurs when data is received or transmitted. I also need to understand what happens in the event of any errors, and whether there's any sophisticated queuing or rate-limiting mechanism employed here. This section is likely to be critical in understanding the overall performance and reliability of the vsock communication. My expert intuition is telling me that this will be an interesting snippet of the codebase to explore. |
| 16/2 | 2026/09/21 11:06 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/virtio_transport_common.c",
"FirstLine": 965,
"LineCount": 40
}Results: {
"Contents": " 965:\t}\n 966:\tEXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);\n 967:\t\n 968:\tstatic u32 virtio_transport_tx_buf_size(struct virtio_vsock_sock *vvs)\n 969:\t{\n 970:\t\t/* The peer advertises its receive buffer via peer_buf_alloc, but we\n 971:\t\t * cap it to our local buf_alloc so a remote peer cannot force us to\n 972:\t\t * queue more data than our own buffer configuration allows.\n 973:\t\t */\n 974:\t\treturn min(vvs-\u003epeer_buf_alloc, vvs-\u003ebuf_alloc);\n 975:\t}\n 976:\t\n 977:\tint\n 978:\tvirtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\n 979:\t\t\t\t\t struct msghdr *msg,\n 980:\t\t\t\t\t size_t len)\n 981:\t{\n 982:\t\tstruct virtio_vsock_sock *vvs = vsk-\u003etrans;\n 983:\t\n 984:\t\tspin_lock_bh(\u0026vvs-\u003etx_lock);\n 985:\t\n 986:\t\tif (len \u003e virtio_transport_tx_buf_size(vvs)) {\n 987:\t\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n 988:\t\t\treturn -EMSGSIZE;\n 989:\t\t}\n 990:\t\n 991:\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n 992:\t\n 993:\t\treturn virtio_transport_stream_enqueue(vsk, msg, len);\n 994:\t}\n 995:\tEXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);\n 996:\t\n 997:\tu32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)\n 998:\t{\n 999:\t\tstruct virtio_vsock_sock *vvs = vsk-\u003etrans;\n1000:\t\tu32 max_size;\n1001:\t\n1002:\t\tspin_lock_bh(\u0026vvs-\u003etx_lock);\n1003:\t\tmax_size = virtio_transport_tx_buf_size(vvs);\n1004:\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n"
} |
| 17/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 18970 output: 17 thoughts: 782 Thoughts: **Analyzing the virtio-vsock Seqpacket Enqueue Behavior** Okay, let's break this down. I'm looking at `virtio_transport_seqpacket_enqueue` and then `af_vsock.c` to understand the flow for `SOCK_SEQPACKET` messages, specifically within a virtio-vsock context. Initially, the `virtio_transport_seqpacket_enqueue` function looks pretty straightforward. It checks if the message size exceeds the available buffer; if so, it returns an error. Otherwise, it calls `virtio_transport_stream_enqueue`. The problem I see is that `virtio_transport_stream_enqueue` is designed to send what it can, potentially sending *partial* packets if the message doesn't fit in the buffer all at once, marking EOM only when the entire message is fully sent. Previously, the code in `vsock_connectible_sendmsg` wasn't handling partial sends correctly for `SOCK_SEQPACKET`. It *would* send what it could. If the send loop got interrupted, say by `-EINTR`, we could end up with a sequence of packets without the EOM marker on the last fragmented packet. This is problematic! The receiving end would treat these partial packets as if they belonged to the next message. So, the fix is in `vsock_connectible_sendmsg`. We now check if it's a `SOCK_SEQPACKET`. If it is, before even attempting to enqueue, we check if the entire *remaining* message can fit. If it can't, `-EMSGSIZE` is returned. If it *can* fit, then we wait for enough space to enqueue the entire remaining portion. This ensures atomicity; the whole message is sent, or none of it is. The key change is this check: `if (transport->seqpacket_max_size && len > transport->seqpacket_max_size(vsk))`. This prevents the "partial packet with no EOM" issue. This `seqpacket_max_size` function is where we would get the total size of the buffer. Now, a critical question arises: *Is this code even reachable?* We have the `af_vsock.c` source code, but is it used? The answer is *YES*. I need to confirm the configuration but the code is indeed used. `vsock_loopback` (which allows local connections using CID 1 without even the hypervisor in the loop) and `virtio_transport` (the standard virtio-vsock device) are both standard components in Linux. I'll need to double-check the Kconfig options for `AF_VSOCK`, `VHOST_VSOCK`, and `VIRTIO_VSOCKETS`, but the general idea is clear: it's possible to hit this code path in a normal QEMU or virtualized environment. |
| 18/2 | 2026/09/21 11:06 | tool | grepper |
0mArgs:{
"Expression": "config VSOCK"
}Results: {
"Output": "drivers/net/Kconfig=472=config NET_VRF\n--\ndrivers/net/Kconfig-480-\ndrivers/net/Kconfig:481:config VSOCKMON\ndrivers/net/Kconfig-482-\ttristate \"Virtual vsock monitoring device\"\n--\nnet/vmw_vsock/Kconfig-5-\nnet/vmw_vsock/Kconfig:6:config VSOCKETS\nnet/vmw_vsock/Kconfig-7-\ttristate \"Virtual Socket protocol\"\n--\nnet/vmw_vsock/Kconfig-18-\nnet/vmw_vsock/Kconfig:19:config VSOCKETS_DIAG\nnet/vmw_vsock/Kconfig-20-\ttristate \"Virtual Sockets monitoring interface\"\n--\nnet/vmw_vsock/Kconfig-28-\nnet/vmw_vsock/Kconfig:29:config VSOCKETS_LOOPBACK\nnet/vmw_vsock/Kconfig-30-\ttristate \"Virtual Sockets loopback transport\"\n"
} |
| 19/2 | 2026/09/21 11:06 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 20664 output: 36 thoughts: 16 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Analyzing the VMWare VSOCK Kconfig** Alright, let's dive into the `net/vmw_vsock/Kconfig` file. I need to understand the configuration options for the VMWare VSOCK driver. My initial goal is to quickly grasp the dependencies, default settings, and any conditional build logic that dictates when and how this driver is included in the kernel build. I'm looking for anything that might impact its behavior or integration with other networking components. Specifically, I'm anticipating the standard Kconfig structure: a `config` block defining the top-level option, likely `VMW_VSOCK`, and its associated `bool` or `tristate` type. I'll be looking for a description, which should give me a high-level overview of what the module does. Then, the meat of it: the `depends on` clauses. These are crucial. I need to see which other kernel features or hardware configurations are prerequisites for VMWare VSOCK to function correctly. This is where the potential gotchas usually hide. Are there any hardware acceleration features or dependencies on other networking subsystems like `CONFIG_NET` or `CONFIG_INET`? Next, I'll pay attention to the `default` value, if any. Is the module enabled by default? If not, what's the logic behind the default state? This gives insights into the maintainers' intentions and the general use-case of the driver. Also, I'll be interested if any menu entries are based on the state of the parent menu entry. Finally, I'll run my eyes through the remainder of the file. Are there any sub-options or fine-grained configurations? Any device-specific settings? I'm hoping to quickly identify the crucial parameters that an administrator might need to tweak for optimal performance or compatibility. I'll need to know if the configuration exposes anything to user-space that may affect how the driver's behaviour and performance. If there are any `select` statements, I need to know what they select. Any `help` text will be valuable for future debugging and configuration. I need to ensure that the dependencies and menu structure are not overly complex and ensure the driver and feature are integrated correctly. Overall, I'm looking for a solid, clear picture of how VMWare VSOCK fits into the kernel ecosystem and what considerations I need to keep in mind when dealing with it. Understanding the Kconfig is the first step. |
| 20/2 | 2026/09/21 11:07 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/Kconfig",
"FirstLine": 1,
"LineCount": 80
}Results: {
"Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\t#\n 3:\t# Vsock protocol\n 4:\t#\n 5:\t\n 6:\tconfig VSOCKETS\n 7:\t\ttristate \"Virtual Socket protocol\"\n 8:\t\thelp\n 9:\t\t Virtual Socket Protocol is a socket protocol similar to TCP/IP\n 10:\t\t allowing communication between Virtual Machines and hypervisor\n 11:\t\t or host.\n 12:\t\n 13:\t\t You should also select one or more hypervisor-specific transports\n 14:\t\t below.\n 15:\t\n 16:\t\t To compile this driver as a module, choose M here: the module\n 17:\t\t will be called vsock. If unsure, say N.\n 18:\t\n 19:\tconfig VSOCKETS_DIAG\n 20:\t\ttristate \"Virtual Sockets monitoring interface\"\n 21:\t\tdepends on VSOCKETS\n 22:\t\tdefault y\n 23:\t\thelp\n 24:\t\t Support for PF_VSOCK sockets monitoring interface used by the ss tool.\n 25:\t\t If unsure, say Y.\n 26:\t\n 27:\t\t Enable this module so userspace applications can query open sockets.\n 28:\t\n 29:\tconfig VSOCKETS_LOOPBACK\n 30:\t\ttristate \"Virtual Sockets loopback transport\"\n 31:\t\tdepends on VSOCKETS\n 32:\t\tdefault y\n 33:\t\tselect VIRTIO_VSOCKETS_COMMON\n 34:\t\thelp\n 35:\t\t This module implements a loopback transport for Virtual Sockets,\n 36:\t\t using vmw_vsock_virtio_transport_common.\n 37:\t\n 38:\t\t To compile this driver as a module, choose M here: the module\n 39:\t\t will be called vsock_loopback. If unsure, say N.\n 40:\t\n 41:\tconfig VMWARE_VMCI_VSOCKETS\n 42:\t\ttristate \"VMware VMCI transport for Virtual Sockets\"\n 43:\t\tdepends on VSOCKETS \u0026\u0026 VMWARE_VMCI\n 44:\t\thelp\n 45:\t\t This module implements a VMCI transport for Virtual Sockets.\n 46:\t\n 47:\t\t Enable this transport if your Virtual Machine runs on a VMware\n 48:\t\t hypervisor.\n 49:\t\n 50:\t\t To compile this driver as a module, choose M here: the module\n 51:\t\t will be called vmw_vsock_vmci_transport. If unsure, say N.\n 52:\t\n 53:\tconfig VIRTIO_VSOCKETS\n 54:\t\ttristate \"virtio transport for Virtual Sockets\"\n 55:\t\tdepends on VSOCKETS \u0026\u0026 VIRTIO\n 56:\t\tselect VIRTIO_VSOCKETS_COMMON\n 57:\t\thelp\n 58:\t\t This module implements a virtio transport for Virtual Sockets.\n 59:\t\n 60:\t\t Enable this transport if your Virtual Machine host supports Virtual\n 61:\t\t Sockets over virtio.\n 62:\t\n 63:\t\t To compile this driver as a module, choose M here: the module will be\n 64:\t\t called vmw_vsock_virtio_transport. If unsure, say N.\n 65:\t\n 66:\tconfig VIRTIO_VSOCKETS_COMMON\n 67:\t\ttristate\n 68:\t\thelp\n 69:\t\t This option is selected by any driver which needs to access\n 70:\t\t the virtio_vsock. The module will be called\n 71:\t\t vmw_vsock_virtio_transport_common.\n 72:\t\n 73:\tconfig HYPERV_VSOCKETS\n 74:\t\ttristate \"Hyper-V transport for Virtual Sockets\"\n 75:\t\tdepends on VSOCKETS \u0026\u0026 HYPERV_VMBUS\n 76:\t\thelp\n 77:\t\t This module implements a Hyper-V transport for Virtual Sockets.\n 78:\t\n 79:\t\t Enable this transport if your Virtual Machine host supports Virtual\n 80:\t\t Sockets over Hyper-V VMBus.\n"
} |
| 21/2 | 2026/09/21 11:07 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 22322 output: 35 thoughts: 59 Thoughts: **My Initial Thoughts on VSOCK Configuration** Okay, so we're talking `VSOCKETS`, `VSOCKETS_LOOPBACK`, `VIRTIO_VSOCKETS`, and `VIRTIO_VSOCKETS_COMMON` – this immediately tells me we're looking at various aspects of vSockets and how they're implemented, likely encompassing both generic functionality and the Virtio-specific variant. We need to dissect the dependencies. To do that, the makefile is the perfect place to start. I'll check the `net/vmw_vsock/Makefile` file to see how those config options relate to the source files. This will paint a clear picture of what's tied to what and how the build system handles these different pieces. |
| 22/2 | 2026/09/21 11:07 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/Makefile",
"FirstLine": 1,
"LineCount": 40
}Results: {
"Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0\n 2:\tobj-$(CONFIG_VSOCKETS) += vsock.o\n 3:\tobj-$(CONFIG_VSOCKETS_DIAG) += vsock_diag.o\n 4:\tobj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o\n 5:\tobj-$(CONFIG_VIRTIO_VSOCKETS) += vmw_vsock_virtio_transport.o\n 6:\tobj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += vmw_vsock_virtio_transport_common.o\n 7:\tobj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o\n 8:\tobj-$(CONFIG_VSOCKETS_LOOPBACK) += vsock_loopback.o\n 9:\t\n 10:\tvsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o\n 11:\tvsock-$(CONFIG_BPF_SYSCALL) += vsock_bpf.o\n 12:\t\n 13:\tvsock_diag-y += diag.o\n 14:\t\n 15:\tvmw_vsock_vmci_transport-y += vmci_transport.o vmci_transport_notify.o \\\n 16:\t\tvmci_transport_notify_qstate.o\n 17:\t\n 18:\tvmw_vsock_virtio_transport-y += virtio_transport.o\n 19:\t\n 20:\tvmw_vsock_virtio_transport_common-y += virtio_transport_common.o\n 21:\t\n 22:\thv_sock-y += hyperv_transport.o\n"
} |
| 23/2 | 2026/09/21 11:07 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 23029 output: 36 thoughts: 1092 Thoughts: **Analysis of a Patch: VSOCK Sequence Packet Blocking Logic** Okay, let's break this down. My initial assessment is that this patch is touching `af_vsock.c`, `virtio_transport.c`, `virtio_transport_common.c`, `vsock_loopback.c`, and relevant header files. Given my experience, I already know this code is absolutely reachable in standard QEMU and fuzzing environments. `AF_VSOCK` sockets, especially those using `SOCK_SEQPACKET`, are prime targets for fuzzers like syzkaller. The loopback vsock is particularly interesting as it bypasses hardware dependencies. The virtio vsock is also super common as a standard virtio device within QEMU. The patch itself is modifying the blocking logic within `vsock_connectible_sendmsg` specifically for `SOCK_SEQPACKET` sockets. Previously, the send function waited for any space to become available. Now, it waits until a minimum amount of space (`min_space`) is available, which is calculated as `len - total_written`. It also adds a check for the maximum size limit before the loop. This new `seqpacket_max_size` functionality is implemented via a new function, `virtio_transport_seqpacket_max_size`, and is hooked into both the `virtio_transport` and `loopback_transport` structs. Now, from a triage perspective, is this something to focus on? The answer is a clear "yes." It hits all the important checkboxes: It's reachable in standard environments, it's not simply a refactoring or a "trust me" fix, it's a core networking (vsock) function, and it uses reachable protocols (sockets, virtio). It's worth fuzzing. My next step is to nail down the focus symbols. The primary function modified is definitely `vsock_connectible_sendmsg` in `af_vsock.c`. It's not a general-purpose function, so it's directly related to the fix. Then we have the newly added `virtio_transport_seqpacket_max_size` in `virtio_transport_common.c` which is a GPL-exported symbol. Finally the patch changes the `virtio_transport` and `loopback_transport` structs in `virtio_transport.c` and `vsock_loopback.c`, which adds the new size limit function to these. I'll quickly double-check the call paths for any other potentially relevant functions. So, based on the patch, the main focus is on: - `vsock_connectible_sendmsg` - `virtio_transport_seqpacket_max_size` There might be others in the call path, like `virtio_transport_tx_buf_size`, but these two are the ones directly affected by the changes. |
| 24/2 | 2026/09/21 11:07 | tool | grepper |
0mArgs:{
"Expression": "vsock_connectible_sendmsg",
"PathPrefix": "net/vmw_vsock/"
}Results: {
"Output": "net/vmw_vsock/af_vsock.c=2129=static int vsock_connectible_getsockopt(struct socket *sock,\n--\nnet/vmw_vsock/af_vsock.c-2187-\nnet/vmw_vsock/af_vsock.c:2188:static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\nnet/vmw_vsock/af_vsock.c-2189-\t\t\t\t size_t len)\n--\nnet/vmw_vsock/af_vsock.c=2677=static const struct proto_ops vsock_stream_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2691-\t.getsockopt_iter = vsock_connectible_getsockopt,\nnet/vmw_vsock/af_vsock.c:2692:\t.sendmsg = vsock_connectible_sendmsg,\nnet/vmw_vsock/af_vsock.c-2693-\t.recvmsg = vsock_connectible_recvmsg,\n--\nnet/vmw_vsock/af_vsock.c=2699=static const struct proto_ops vsock_seqpacket_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2713-\t.getsockopt_iter = vsock_connectible_getsockopt,\nnet/vmw_vsock/af_vsock.c:2714:\t.sendmsg = vsock_connectible_sendmsg,\nnet/vmw_vsock/af_vsock.c-2715-\t.recvmsg = vsock_connectible_recvmsg,\n"
} |
| 25/2 | 2026/09/21 11:07 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 25221 output: 27 thoughts: 257 Thoughts: **My Analysis of vsock_connectible_sendmsg Compilation** Okay, so `vsock_connectible_sendmsg` is the crucial `sendmsg` function used by both `vsock_stream_ops` and `vsock_seqpacket_ops`. I need to figure out the exact configuration options needed to compile and, more importantly, *reach* these functions in the kernel. Let's dig into the relevant Kconfig and Makefile. Looking at `net/vmw_vsock/Kconfig` and `net/vmw_vsock/Makefile`, it's clear that `af_vsock.o` relies on `CONFIG_VSOCKETS`. That's the baseline. The more interesting piece is `virtio_transport_common.o`, which is compiled when `CONFIG_VIRTIO_VSOCKETS_COMMON` is enabled. Now, where does `CONFIG_VIRTIO_VSOCKETS_COMMON` come from? Well, it's selected by either `CONFIG_VSOCKETS_LOOPBACK`, which is a loopback transport, and, importantly, depends on `VSOCKETS`, with a default of 'y', and also `CONFIG_VIRTIO_VSOCKETS`, which is the actual virtio transport and, naturally, depends on `VSOCKETS` and `VIRTIO`. I need to make sure I haven't missed any other dependencies. Since `VSOCKETS` is at the core of all this, I should quickly check if it, itself, depends on a higher-level network option like `NET`. I'll glance at `net/Kconfig` to confirm that. Gotta be thorough. |
| 26/2 | 2026/09/21 11:07 | tool | grepper |
0mArgs:{
"Expression": "source \"net/vmw_vsock/Kconfig\""
}Results: {
"Output": "net/Kconfig=274=source \"net/openvswitch/Kconfig\"\nnet/Kconfig:275:source \"net/vmw_vsock/Kconfig\"\nnet/Kconfig-276-source \"net/netlink/Kconfig\"\n"
} |
| 27/2 | 2026/09/21 11:07 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 25937 output: 193 thoughts: 614 Thoughts: **My Assessment of the VSOCK Patch** Okay, let's break this down. From what I see in `net/vmw_vsock/Kconfig`, it looks like the patch I'm examining primarily concerns the Virtual Sockets (VSOCKETS) implementation. To get a handle on it, I need to make sure `VSOCKETS`, `VSOCKETS_LOOPBACK`, and `VIRTIO_VSOCKETS` are enabled in the kernel configuration. I should probably also confirm that `VIRTIO` is enabled, although that's usually standard on most architectures these days. It looks like `VIRTIO_VSOCKETS_COMMON` is selected by the loopback and virtio transports, which is expected. No other configs seem relevant here. The patch modifies `af_vsock.c`, `virtio_transport.c`, `virtio_transport_common.c`, and `vsock_loopback.c`, which tells me this is focused on transport-level functionality, specifically, the send path for `SOCK_SEQPACKET` sockets within `AF_VSOCK`. The core of the change appears to be in `vsock_connectible_sendmsg()`, where it's enforcing stricter credit management and message size limitations. Specifically, this ensures that a full SEQPACKET message is sent only when there's sufficient credit, and rejects overly large messages with `-EMSGSIZE` using `transport->seqpacket_max_size()`, which translates to `virtio_transport_seqpacket_max_size()`. This is crucial. Those changes are likely to have a direct impact on the blocking behavior, credit tracking, timeouts, signal handling, and packet sizing of AF_VSOCK socket communication. I can test this using either the loopback or virtio transport. Given the potential impact on critical socket functionality, this is definitely WorthFuzzing. The key symbols I need to focus on are `vsock_connectible_sendmsg` and `virtio_transport_seqpacket_max_size`. All seems to be in order. I'm ready to call `set-results`. |
| 28/2 | 2026/09/21 11:07 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"VSOCKETS",
"VSOCKETS_LOOPBACK",
"VIRTIO_VSOCKETS"
],
"FocusSymbols": [
"vsock_connectible_sendmsg",
"virtio_transport_seqpacket_max_size"
],
"Reasoning": "The patch modifies the send path for AF_VSOCK SOCK_SEQPACKET sockets in vsock_connectible_sendmsg() to ensure atomicity by requiring enough buffer space for the entire message before enqueueing, and introduces an up-front message size check via the new transport callback seqpacket_max_size (implemented as virtio_transport_seqpacket_max_size for virtio and loopback transports). This reachable core networking socket path alters blocking wait semantics, signal handling, and error handling, making it an ideal target for fuzzing.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"VSOCKETS",
"VSOCKETS_LOOPBACK",
"VIRTIO_VSOCKETS"
],
"FocusSymbols": [
"vsock_connectible_sendmsg",
"virtio_transport_seqpacket_max_size"
],
"Reasoning": "The patch modifies the send path for AF_VSOCK SOCK_SEQPACKET sockets in vsock_connectible_sendmsg() to ensure atomicity by requiring enough buffer space for the entire message before enqueueing, and introduces an up-front message size check via the new transport callback seqpacket_max_size (implemented as virtio_transport_seqpacket_max_size for virtio and loopback transports). This reachable core networking socket path alters blocking wait semantics, signal handling, and error handling, making it an ideal target for fuzzing.",
"WorthFuzzing": true
} |
| 29/1 | 2026/09/21 11:07 | action | If |
2mArgs:{
"WorthFuzzing": true
}Results: null |
| 30/2 | 2026/09/21 11:07 | agent | kmsan-evaluator |
2mModel:core Args: null Results: {
"KMSANReasoning": "The patch introduces flow-control improvements for SOCK_SEQPACKET in AF_VSOCK (virtio transport). Specifically, it ensures that SEQPACKET messages wait until sufficient space is available (min_space = len - total_written) before enqueueing, and rejects oversized messages up-front via a new transport callback (`seqpacket_max_size`).\n\nNo uninitialized memory hazards are introduced or exposed:\n1. All newly introduced local variables (`min_space`, `max_size`) are deterministically initialized in all execution branches prior to being read.\n2. No data is copied to user space; the modified path is in the send/transmit path (`vsock_connectible_sendmsg`), moving data from user space into socket buffers.\n3. No kernel heap/stack buffers or structure paddings that could be read or leaked are modified or allocated.\n4. Surrounding buffer bounds and data access logic remain strictly bounded by user-supplied lengths.\n\nAny potential issues arising from this patch (such as deadlocks, lock contention around `tx_lock`, or socket reference handling) fall entirely under LOCKDEP, KASAN, or standard kernel bug detection mechanisms. Thus, a dedicated KMSAN fuzzing session is not justified.",
"NeedsKMSAN": false
}Instruction: You are an expert Linux kernel security engineer specializing in kernel memory
error detectors (KASAN and KMSAN). Your job is to review the provided patch series and
determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer)
fuzzing session in addition to standard KASAN fuzzing.
CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN:
- Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable
a comprehensive suite of debugging tools and sanitizers, including KASAN
(out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP
(locking bugs and deadlocks), UB-sanitizers, and memory corruption checks.
- KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap,
or page allocations) and kernel-to-user memory info-leaks.
Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN,
LOCKDEP, OR OTHER STANDARD BUG DETECTORS.
A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY
set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks
that are detected ONLY by KMSAN.
Look holistically at the patch series and surrounding code. Even if no direct
uninitialized field accesses or new buffer allocations are added in the diff itself,
a patch may alter control flow, bounds checking, or data length calculations in ways
that change how the rest of the code operates on existing buffers (e.g. allowing
uninitialized stack/heap memory to be read, copied to user space, or used in control
flow). Do not hesitate to use your code access tools to inspect the surrounding code,
called functions, and callers.
Set NeedsKMSAN=true ONLY IF the patch introduces or modifies:
1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb
attributes, ioctl output arguments, socket options, or BPF buffers) where fields
or structure padding might not be fully initialized/zeroed.
2. Conditional logic or branching that depends on potentially uninitialized variables
or struct fields.
3. Allocation or initialization of complex data structures where uninitialized fields
could be read later in reachable code paths.
4. Bounds checks, lengths, or logic in a way that allows surrounding code to access
uninitialized bytes of existing buffers.
Set NeedsKMSAN=false IF:
- The code changes primarily risk out-of-bounds access, array overflows, NULL pointer
dereferences, locking deadlocks, or use-after-free bugs (these are already caught
by KASAN, LOCKDEP, or standard bug detectors).
- All stack/heap structures touched or introduced by the patch are fully zeroed
or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied.
- The patch does not introduce any risk of uninitialized memory usage or info-leaks.
Use your code access tools to inspect the surrounding code if necessary, then provide
detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch.
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt: Target architecture: amd64
For your convenience, here is the diff of the changes:
commit 7c72772b3ffb160ac7c2ef59de999c2e584034f8
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Sep 21 11:05:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index f91704731057e..e96790c038963 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -219,6 +219,7 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
u32 virtio_transport_seqpacket_has_data(struct vsock_sock *vsk);
+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk);
ssize_t virtio_transport_unsent_bytes(struct vsock_sock *vsk);
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 5549298c1ec6b..d94c613ef604b 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -143,6 +143,7 @@ struct vsock_transport {
size_t len);
bool (*seqpacket_allow)(struct vsock_sock *vsk, u32 remote_cid);
u32 (*seqpacket_has_data)(struct vsock_sock *vsk);
+ u32 (*seqpacket_max_size)(struct vsock_sock *vsk);
/* Notification. */
int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index f840498b58afb..ac64cb9571643 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2250,9 +2250,32 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
while (total_written < len) {
ssize_t written;
+ s64 min_space;
+
+ if (sk->sk_type == SOCK_SEQPACKET) {
+ /* A SEQPACKET message must be delivered atomically, so
+ * wait until the whole remaining message fits before
+ * enqueuing. Otherwise a credit-limited partial send that
+ * later errors out (e.g. -EINTR) leaves EOM-less fragments
+ * that the peer merges into the next message.
+ *
+ * Reject a message that can never fit up front so the wait
+ * below cannot block forever (a peer may advertise a small
+ * buf_alloc); this mirrors the -EMSGSIZE the transport
+ * returns for an oversized message.
+ */
+ if (transport->seqpacket_max_size &&
+ len > transport->seqpacket_max_size(vsk)) {
+ err = -EMSGSIZE;
+ goto out_err;
+ }
+ min_space = len - total_written;
+ } else {
+ min_space = 1;
+ }
add_wait_queue(sk_sleep(sk), &wait);
- while (vsock_stream_has_space(vsk) == 0 &&
+ while (vsock_stream_has_space(vsk) < min_space &&
sk->sk_err == 0 &&
!(sk->sk_shutdown & SEND_SHUTDOWN) &&
!(vsk->peer_shutdown & RCV_SHUTDOWN)) {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 4f9aa9c4c3aa5..b7d587a202044 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -585,6 +585,7 @@ static struct virtio_transport virtio_transport = {
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = virtio_transport_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
+ .seqpacket_max_size = virtio_transport_seqpacket_max_size,
.msgzerocopy_allow = virtio_transport_msgzerocopy_allow,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index f225f53ed4bab..e10e7b95807e3 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -994,6 +994,19 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
}
EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
+u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ u32 max_size;
+
+ spin_lock_bh(&vvs->tx_lock);
+ max_size = virtio_transport_tx_buf_size(vvs);
+ spin_unlock_bh(&vvs->tx_lock);
+
+ return max_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_max_size);
+
int
virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 8068d1b6e8518..b9a0cc861d495 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -90,6 +90,7 @@ static struct virtio_transport loopback_transport = {
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = vsock_loopback_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
+ .seqpacket_max_size = virtio_transport_seqpacket_max_size,
.msgzerocopy_allow = vsock_loopback_msgzerocopy_allow,
|
| 31/3 | 2026/09/21 11:07 | llm | kmsan-evaluator |
1mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 3759 output: 43 thoughts: 150 Thoughts: **Analyzing the Proposed vsock Patch** Okay, so this patch is definitely poking around in a few key areas of the vsock implementation. I see it touches the core headers: `virtio_vsock.h` and `af_vsock.h`. That immediately tells me this could be a fundamental change. Then, we have the meat of the implementation: `af_vsock.c`, `virtio_transport.c`, `virtio_transport_common.c`, and `vsock_loopback.c`. Given my expertise, I suspect this has to do with connection handling, transport specifics, and loopback functionality. Let's dive into the code. My primary concern will be the implications for socket-level behaviour. I'll start with `net/vmw_vsock/af_vsock.c` around line 2250, specifically focusing on `vsock_connectible_sendmsg`. I want to understand how the changes affect the `sendmsg` path in a connectible vsock context. That function is probably the crux of the changes, because it is at the edge of the socket interface. I want to see how these changes are affecting how we send data over the connection. I'll need to think about potential race conditions and performance implications. |
| 32/3 | 2026/09/21 11:09 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/af_vsock.c",
"FirstLine": 2230,
"LineCount": 80
}Results: {
"Contents": "2230:\t\t\tgoto out;\n2231:\t\t}\n2232:\t\n2233:\t\tif (!vsock_addr_bound(\u0026vsk-\u003eremote_addr)) {\n2234:\t\t\terr = -EDESTADDRREQ;\n2235:\t\t\tgoto out;\n2236:\t\t}\n2237:\t\n2238:\t\tif (msg-\u003emsg_flags \u0026 MSG_ZEROCOPY \u0026\u0026\n2239:\t\t !vsock_msgzerocopy_allow(transport)) {\n2240:\t\t\terr = -EOPNOTSUPP;\n2241:\t\t\tgoto out;\n2242:\t\t}\n2243:\t\n2244:\t\t/* Wait for room in the produce queue to enqueue our user's data. */\n2245:\t\ttimeout = sock_sndtimeo(sk, msg-\u003emsg_flags \u0026 MSG_DONTWAIT);\n2246:\t\n2247:\t\terr = transport-\u003enotify_send_init(vsk, \u0026send_data);\n2248:\t\tif (err \u003c 0)\n2249:\t\t\tgoto out;\n2250:\t\n2251:\t\twhile (total_written \u003c len) {\n2252:\t\t\tssize_t written;\n2253:\t\t\ts64 min_space;\n2254:\t\n2255:\t\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\n2256:\t\t\t\t/* A SEQPACKET message must be delivered atomically, so\n2257:\t\t\t\t * wait until the whole remaining message fits before\n2258:\t\t\t\t * enqueuing. Otherwise a credit-limited partial send that\n2259:\t\t\t\t * later errors out (e.g. -EINTR) leaves EOM-less fragments\n2260:\t\t\t\t * that the peer merges into the next message.\n2261:\t\t\t\t *\n2262:\t\t\t\t * Reject a message that can never fit up front so the wait\n2263:\t\t\t\t * below cannot block forever (a peer may advertise a small\n2264:\t\t\t\t * buf_alloc); this mirrors the -EMSGSIZE the transport\n2265:\t\t\t\t * returns for an oversized message.\n2266:\t\t\t\t */\n2267:\t\t\t\tif (transport-\u003eseqpacket_max_size \u0026\u0026\n2268:\t\t\t\t len \u003e transport-\u003eseqpacket_max_size(vsk)) {\n2269:\t\t\t\t\terr = -EMSGSIZE;\n2270:\t\t\t\t\tgoto out_err;\n2271:\t\t\t\t}\n2272:\t\t\t\tmin_space = len - total_written;\n2273:\t\t\t} else {\n2274:\t\t\t\tmin_space = 1;\n2275:\t\t\t}\n2276:\t\n2277:\t\t\tadd_wait_queue(sk_sleep(sk), \u0026wait);\n2278:\t\t\twhile (vsock_stream_has_space(vsk) \u003c min_space \u0026\u0026\n2279:\t\t\t sk-\u003esk_err == 0 \u0026\u0026\n2280:\t\t\t !(sk-\u003esk_shutdown \u0026 SEND_SHUTDOWN) \u0026\u0026\n2281:\t\t\t !(vsk-\u003epeer_shutdown \u0026 RCV_SHUTDOWN)) {\n2282:\t\n2283:\t\t\t\t/* Don't wait for non-blocking sockets. */\n2284:\t\t\t\tif (timeout == 0) {\n2285:\t\t\t\t\terr = -EAGAIN;\n2286:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2287:\t\t\t\t\tgoto out_err;\n2288:\t\t\t\t}\n2289:\t\n2290:\t\t\t\terr = transport-\u003enotify_send_pre_block(vsk, \u0026send_data);\n2291:\t\t\t\tif (err \u003c 0) {\n2292:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2293:\t\t\t\t\tgoto out_err;\n2294:\t\t\t\t}\n2295:\t\n2296:\t\t\t\trelease_sock(sk);\n2297:\t\t\t\ttimeout = wait_woken(\u0026wait, TASK_INTERRUPTIBLE, timeout);\n2298:\t\t\t\tlock_sock(sk);\n2299:\t\t\t\tif (signal_pending(current)) {\n2300:\t\t\t\t\terr = sock_intr_errno(timeout);\n2301:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2302:\t\t\t\t\tgoto out_err;\n2303:\t\t\t\t} else if (timeout == 0) {\n2304:\t\t\t\t\terr = -EAGAIN;\n2305:\t\t\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n2306:\t\t\t\t\tgoto out_err;\n2307:\t\t\t\t}\n2308:\t\t\t}\n2309:\t\t\tremove_wait_queue(sk_sleep(sk), \u0026wait);\n"
} |
| 33/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 5447 output: 43 thoughts: 20 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Diving Deeper into `vsock_connectible_sendmsg`** Okay, so we've looked at part of the `vsock_connectible_sendmsg` function. I need to get the bigger picture, so let's continue dissecting this thing. What's the complete flow? What are the edge cases? I want to see the error handling, the resource management, and how this integrates with the rest of the vsock stack. Need to fully understand the interaction with the socket itself, the control flow for connection establishment, and the intricacies of sending data over a connected vsock. Gotta know all the ins and outs. |
| 34/3 | 2026/09/21 11:09 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/af_vsock.c",
"FirstLine": 2310,
"LineCount": 60
}Results: {
"Contents": "2310:\t\n2311:\t\t\t/* These checks occur both as part of and after the loop\n2312:\t\t\t * conditional since we need to check before and after\n2313:\t\t\t * sleeping.\n2314:\t\t\t */\n2315:\t\t\tif (sk-\u003esk_err) {\n2316:\t\t\t\terr = -sk-\u003esk_err;\n2317:\t\t\t\tgoto out_err;\n2318:\t\t\t} else if ((sk-\u003esk_shutdown \u0026 SEND_SHUTDOWN) ||\n2319:\t\t\t\t (vsk-\u003epeer_shutdown \u0026 RCV_SHUTDOWN)) {\n2320:\t\t\t\terr = -EPIPE;\n2321:\t\t\t\tgoto out_err;\n2322:\t\t\t}\n2323:\t\n2324:\t\t\terr = transport-\u003enotify_send_pre_enqueue(vsk, \u0026send_data);\n2325:\t\t\tif (err \u003c 0)\n2326:\t\t\t\tgoto out_err;\n2327:\t\n2328:\t\t\t/* Note that enqueue will only write as many bytes as are free\n2329:\t\t\t * in the produce queue, so we don't need to ensure len is\n2330:\t\t\t * smaller than the queue size. It is the caller's\n2331:\t\t\t * responsibility to check how many bytes we were able to send.\n2332:\t\t\t */\n2333:\t\n2334:\t\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\n2335:\t\t\t\twritten = transport-\u003eseqpacket_enqueue(vsk,\n2336:\t\t\t\t\t\t\tmsg, len - total_written);\n2337:\t\t\t} else {\n2338:\t\t\t\twritten = transport-\u003estream_enqueue(vsk,\n2339:\t\t\t\t\t\tmsg, len - total_written);\n2340:\t\t\t}\n2341:\t\n2342:\t\t\tif (written \u003c 0) {\n2343:\t\t\t\terr = written;\n2344:\t\t\t\tgoto out_err;\n2345:\t\t\t}\n2346:\t\n2347:\t\t\ttotal_written += written;\n2348:\t\n2349:\t\t\terr = transport-\u003enotify_send_post_enqueue(\n2350:\t\t\t\t\tvsk, written, \u0026send_data);\n2351:\t\t\tif (err \u003c 0)\n2352:\t\t\t\tgoto out_err;\n2353:\t\n2354:\t\t}\n2355:\t\n2356:\tout_err:\n2357:\t\tif (total_written \u003e 0) {\n2358:\t\t\t/* Return number of written bytes only if:\n2359:\t\t\t * 1) SOCK_STREAM socket.\n2360:\t\t\t * 2) SOCK_SEQPACKET socket when whole buffer is sent.\n2361:\t\t\t */\n2362:\t\t\tif (sk-\u003esk_type == SOCK_STREAM || total_written == len)\n2363:\t\t\t\terr = total_written;\n2364:\t\t}\n2365:\tout:\n2366:\t\tif (sk-\u003esk_type == SOCK_STREAM)\n2367:\t\t\terr = sk_stream_error(sk, msg-\u003emsg_flags, err);\n2368:\t\n2369:\t\trelease_sock(sk);\n"
} |
| 35/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 6512 output: 38 thoughts: 48 Thoughts: Okay, let's dive into this. Here's my thought process on the matter: **Digging into the Virtio vsock Implementation** Right, so we're looking at the network layer of the Virtio vsock implementation. We need to go further down the rabbit hole than what we've already found. Specifically, I need to check how the packet enqueueing is handled, and also, I'm thinking, is `virtio_transport_tx_buf_size` important here too? I'll need to examine `virtio_transport_seqpacket_enqueue` and then `virtio_transport_tx_buf_size` inside `net/vmw_vsock/virtio_transport_common.c`. It's likely that these two pieces have a role to play in the behavior we're seeing. Time to get my hands dirty. |
| 36/3 | 2026/09/21 11:09 | tool | grepper |
0mArgs:{
"Expression": "virtio_transport_tx_buf_size",
"PathPrefix": "net/vmw_vsock/"
}Results: {
"Output": "net/vmw_vsock/virtio_transport_common.c=966=EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);\nnet/vmw_vsock/virtio_transport_common.c-967-\nnet/vmw_vsock/virtio_transport_common.c:968:static u32 virtio_transport_tx_buf_size(struct virtio_vsock_sock *vvs)\nnet/vmw_vsock/virtio_transport_common.c-969-{\n--\nnet/vmw_vsock/virtio_transport_common.c=978=virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\n--\nnet/vmw_vsock/virtio_transport_common.c-985-\nnet/vmw_vsock/virtio_transport_common.c:986:\tif (len \u003e virtio_transport_tx_buf_size(vvs)) {\nnet/vmw_vsock/virtio_transport_common.c-987-\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n--\nnet/vmw_vsock/virtio_transport_common.c=997=u32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/virtio_transport_common.c-1002-\tspin_lock_bh(\u0026vvs-\u003etx_lock);\nnet/vmw_vsock/virtio_transport_common.c:1003:\tmax_size = virtio_transport_tx_buf_size(vvs);\nnet/vmw_vsock/virtio_transport_common.c-1004-\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n--\nnet/vmw_vsock/virtio_transport_common.c=1045=static s64 virtio_transport_has_space(struct virtio_vsock_sock *vvs)\n--\nnet/vmw_vsock/virtio_transport_common.c-1052-\t */\nnet/vmw_vsock/virtio_transport_common.c:1053:\tbytes = (s64)virtio_transport_tx_buf_size(vvs) -\nnet/vmw_vsock/virtio_transport_common.c-1054-\t\t(vvs-\u003etx_cnt - vvs-\u003epeer_fwd_cnt);\n"
} |
| 37/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 7404 output: 44 thoughts: 28 Thoughts: Okay, let's dive into this code. **Analyzing `virtio_transport_tx_buf_size` and `virtio_transport_seqpacket_enqueue`** Alright, I'm going to take a look at these two functions – `virtio_transport_tx_buf_size` and `virtio_transport_seqpacket_enqueue`. Immediately, I'm thinking about how these relate to the transport layer in a VirtIO environment, specifically handling transmit buffer sizing and enqueuing packets, likely for a sequential packet (like TCP-like) interface. `tx_buf_size` suggests a function that determines the appropriate buffer size for a transmit operation, maybe based on the device's capabilities, packet size, or available resources. I want to see how that calculation is done, what factors are considered, and if there are any error handling mechanisms in place if the requested buffer size is unacceptable. Then there's `virtio_transport_seqpacket_enqueue`. This screams "packet transmission" to me. I'm assuming this function is responsible for actually taking the data, constructing the VirtIO descriptors, and putting the packet into the transmit queue. I'll need to understand the details of the VirtIO descriptor setup, how the DMA operations are handled, the potential for descriptor chaining, and the implications for interrupt handling upon completion. I'm keen to see if any flow control or rate limiting is implemented here, and how this enqueue function interacts with the underlying hardware's transmit ring buffer. I also want to check for any potential race conditions if there are other threads accessing the same structures. I'll also be mindful of how the enqueue function interacts with the scatter-gather lists to see if the device can handle fragmented packets, which can lead to performance boosts. I'm hoping it's well-designed and avoids unnecessary copies. Overall, I want to understand how the data is being moved from the application space, through the VirtIO layer, to the hardware. |
| 38/3 | 2026/09/21 11:09 | tool | read-file |
0mArgs:{
"File": "net/vmw_vsock/virtio_transport_common.c",
"FirstLine": 965,
"LineCount": 45
}Results: {
"Contents": " 965:\t}\n 966:\tEXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);\n 967:\t\n 968:\tstatic u32 virtio_transport_tx_buf_size(struct virtio_vsock_sock *vvs)\n 969:\t{\n 970:\t\t/* The peer advertises its receive buffer via peer_buf_alloc, but we\n 971:\t\t * cap it to our local buf_alloc so a remote peer cannot force us to\n 972:\t\t * queue more data than our own buffer configuration allows.\n 973:\t\t */\n 974:\t\treturn min(vvs-\u003epeer_buf_alloc, vvs-\u003ebuf_alloc);\n 975:\t}\n 976:\t\n 977:\tint\n 978:\tvirtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\n 979:\t\t\t\t\t struct msghdr *msg,\n 980:\t\t\t\t\t size_t len)\n 981:\t{\n 982:\t\tstruct virtio_vsock_sock *vvs = vsk-\u003etrans;\n 983:\t\n 984:\t\tspin_lock_bh(\u0026vvs-\u003etx_lock);\n 985:\t\n 986:\t\tif (len \u003e virtio_transport_tx_buf_size(vvs)) {\n 987:\t\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n 988:\t\t\treturn -EMSGSIZE;\n 989:\t\t}\n 990:\t\n 991:\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n 992:\t\n 993:\t\treturn virtio_transport_stream_enqueue(vsk, msg, len);\n 994:\t}\n 995:\tEXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);\n 996:\t\n 997:\tu32 virtio_transport_seqpacket_max_size(struct vsock_sock *vsk)\n 998:\t{\n 999:\t\tstruct virtio_vsock_sock *vvs = vsk-\u003etrans;\n1000:\t\tu32 max_size;\n1001:\t\n1002:\t\tspin_lock_bh(\u0026vvs-\u003etx_lock);\n1003:\t\tmax_size = virtio_transport_tx_buf_size(vvs);\n1004:\t\tspin_unlock_bh(\u0026vvs-\u003etx_lock);\n1005:\t\n1006:\t\treturn max_size;\n1007:\t}\n1008:\tEXPORT_SYMBOL_GPL(virtio_transport_seqpacket_max_size);\n1009:\t\n"
} |
| 39/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 8600 output: 32 thoughts: 37 Thoughts: Okay, let's break this down. **Investigating vsock Transports** Alright, so I need to get a handle on the available transport mechanisms for vsock. First things first, what's out there? I'm thinking I should start with the known quantities: `virtio_transport` is definitely on the list, and then there's `vsock_loopback`. That's a solid baseline. Now, a bit of a question mark: what about `vhost/vsock`? I'm fairly certain I've seen that mentioned in relation to vsock, but I need to confirm its role and details here. Time to dig deeper and see what that one's all about. |
| 40/3 | 2026/09/21 11:09 | tool | grepper |
0mArgs:{
"Expression": "seqpacket_enqueue",
"PathPrefix": "net/vmw_vsock/"
}Results: {
"Output": "net/vmw_vsock/af_vsock.c=2188=static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2334-\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\nnet/vmw_vsock/af_vsock.c:2335:\t\t\twritten = transport-\u003eseqpacket_enqueue(vsk,\nnet/vmw_vsock/af_vsock.c-2336-\t\t\t\t\t\tmsg, len - total_written);\n--\nnet/vmw_vsock/virtio_transport.c=557=static struct virtio_transport virtio_transport = {\n--\nnet/vmw_vsock/virtio_transport.c-584-\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\nnet/vmw_vsock/virtio_transport.c:585:\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/virtio_transport.c-586-\t\t.seqpacket_allow = virtio_transport_seqpacket_allow,\n--\nnet/vmw_vsock/virtio_transport_common.c=977=int\nnet/vmw_vsock/virtio_transport_common.c:978:virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\nnet/vmw_vsock/virtio_transport_common.c-979-\t\t\t\t struct msghdr *msg,\n--\nnet/vmw_vsock/virtio_transport_common.c-994-}\nnet/vmw_vsock/virtio_transport_common.c:995:EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);\nnet/vmw_vsock/virtio_transport_common.c-996-\n--\nnet/vmw_vsock/vsock_loopback.c=63=static struct virtio_transport loopback_transport = {\n--\nnet/vmw_vsock/vsock_loopback.c-89-\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\nnet/vmw_vsock/vsock_loopback.c:90:\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/vsock_loopback.c-91-\t\t.seqpacket_allow = vsock_loopback_seqpacket_allow,\n"
} |
| 41/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 9465 output: 18 thoughts: 23 Thoughts: Okay, here's my attempt at summarizing that thought process, tailored for an expert audience: **Investigating Potential Bottlenecks in vhost/seqpacket Integration** Right, so we're looking at performance within the vhost context, specifically the interplay with `seqpacket`. My immediate thought is, beyond the usual suspects, where else could we be seeing contention or unexpected behavior? I need to quickly scan for usage of `seqpacket_enqueue` and its interaction points. I'm going to leverage `grep` to quickly search the codebase. Since we are looking into the `vhost` subsystem, I should start the search within `drivers/vhost` but I'll make the scope broader to encompass the entire tree to be thorough. We should look to find all the places it's being called, focusing on the context where it gets called, how arguments are passed, and potential locking that might be involved. This should help to identify any areas where a bottleneck might arise, or unexpected contention. |
| 42/3 | 2026/09/21 11:09 | tool | grepper |
0mArgs:{
"Expression": "seqpacket_enqueue"
}Results: {
"Output": "drivers/vhost/vsock.c=450=static struct virtio_transport vhost_transport = {\n--\ndrivers/vhost/vsock.c-477-\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\ndrivers/vhost/vsock.c:478:\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\ndrivers/vhost/vsock.c-479-\t\t.seqpacket_allow = vhost_transport_seqpacket_allow,\n--\ninclude/linux/virtio_vsock.h=211=int\ninclude/linux/virtio_vsock.h:212:virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\ninclude/linux/virtio_vsock.h-213-\t\t\t\t struct msghdr *msg,\n--\ninclude/net/af_vsock.h=105=struct vsock_transport {\n--\ninclude/net/af_vsock.h-141-\t\t\t\t int flags);\ninclude/net/af_vsock.h:142:\tint (*seqpacket_enqueue)(struct vsock_sock *vsk, struct msghdr *msg,\ninclude/net/af_vsock.h-143-\t\t\t\t size_t len);\n--\nnet/vmw_vsock/af_vsock.c=2188=static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2334-\t\tif (sk-\u003esk_type == SOCK_SEQPACKET) {\nnet/vmw_vsock/af_vsock.c:2335:\t\t\twritten = transport-\u003eseqpacket_enqueue(vsk,\nnet/vmw_vsock/af_vsock.c-2336-\t\t\t\t\t\tmsg, len - total_written);\n--\nnet/vmw_vsock/virtio_transport.c=557=static struct virtio_transport virtio_transport = {\n--\nnet/vmw_vsock/virtio_transport.c-584-\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\nnet/vmw_vsock/virtio_transport.c:585:\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/virtio_transport.c-586-\t\t.seqpacket_allow = virtio_transport_seqpacket_allow,\n--\nnet/vmw_vsock/virtio_transport_common.c=977=int\nnet/vmw_vsock/virtio_transport_common.c:978:virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,\nnet/vmw_vsock/virtio_transport_common.c-979-\t\t\t\t struct msghdr *msg,\n--\nnet/vmw_vsock/virtio_transport_common.c-994-}\nnet/vmw_vsock/virtio_transport_common.c:995:EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);\nnet/vmw_vsock/virtio_transport_common.c-996-\n--\nnet/vmw_vsock/vsock_loopback.c=63=static struct virtio_transport loopback_transport = {\n--\nnet/vmw_vsock/vsock_loopback.c-89-\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\nnet/vmw_vsock/vsock_loopback.c:90:\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\nnet/vmw_vsock/vsock_loopback.c-91-\t\t.seqpacket_allow = vsock_loopback_seqpacket_allow,\n"
} |
| 43/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 10679 output: 37 thoughts: 79 Thoughts: Here's my thinking process: **Diving into the vhost-vsock Implementation** Okay, so I'm looking at `drivers/vhost/vsock.c` and immediately my attention is caught by `vhost_transport` using `virtio_transport_seqpacket_enqueue`. That's interesting, I need to make a mental note of that relationship. Now, did the recent patch I was reviewing touch this file? I need to quickly confirm whether or not this is something new that I missed. Hang on... let me go back into the code, and focus on that file. Specifically, I'll direct my attention around line 478. Let's see what's going on there. I'll need to examine that part of the code in more detail. |
| 44/3 | 2026/09/21 11:09 | tool | read-file |
0mArgs:{
"File": "drivers/vhost/vsock.c",
"FirstLine": 460,
"LineCount": 40
}Results: {
"Contents": " 460:\t\t\t.connect = virtio_transport_connect,\n 461:\t\t\t.shutdown = virtio_transport_shutdown,\n 462:\t\t\t.cancel_pkt = vhost_transport_cancel_pkt,\n 463:\t\n 464:\t\t\t.dgram_enqueue = virtio_transport_dgram_enqueue,\n 465:\t\t\t.dgram_dequeue = virtio_transport_dgram_dequeue,\n 466:\t\t\t.dgram_bind = virtio_transport_dgram_bind,\n 467:\t\t\t.dgram_allow = virtio_transport_dgram_allow,\n 468:\t\n 469:\t\t\t.stream_enqueue = virtio_transport_stream_enqueue,\n 470:\t\t\t.stream_dequeue = virtio_transport_stream_dequeue,\n 471:\t\t\t.stream_has_data = virtio_transport_stream_has_data,\n 472:\t\t\t.stream_has_space = virtio_transport_stream_has_space,\n 473:\t\t\t.stream_rcvhiwat = virtio_transport_stream_rcvhiwat,\n 474:\t\t\t.stream_is_active = virtio_transport_stream_is_active,\n 475:\t\t\t.stream_allow = vhost_transport_stream_allow,\n 476:\t\n 477:\t\t\t.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,\n 478:\t\t\t.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,\n 479:\t\t\t.seqpacket_allow = vhost_transport_seqpacket_allow,\n 480:\t\t\t.seqpacket_has_data = virtio_transport_seqpacket_has_data,\n 481:\t\n 482:\t\t\t.msgzerocopy_allow = vhost_transport_msgzerocopy_allow,\n 483:\t\n 484:\t\t\t.notify_poll_in = virtio_transport_notify_poll_in,\n 485:\t\t\t.notify_poll_out = virtio_transport_notify_poll_out,\n 486:\t\t\t.notify_recv_init = virtio_transport_notify_recv_init,\n 487:\t\t\t.notify_recv_pre_block = virtio_transport_notify_recv_pre_block,\n 488:\t\t\t.notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue,\n 489:\t\t\t.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,\n 490:\t\t\t.notify_send_init = virtio_transport_notify_send_init,\n 491:\t\t\t.notify_send_pre_block = virtio_transport_notify_send_pre_block,\n 492:\t\t\t.notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue,\n 493:\t\t\t.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,\n 494:\t\t\t.notify_buffer_size = virtio_transport_notify_buffer_size,\n 495:\t\t\t.notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,\n 496:\t\n 497:\t\t\t.unsent_bytes = virtio_transport_unsent_bytes,\n 498:\t\n 499:\t\t\t.read_skb = virtio_transport_read_skb,\n"
} |
| 45/3 | 2026/09/21 11:09 | llm | kmsan-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 11867 output: 284 thoughts: 1842 Thoughts: **KMSAN Assessment: No Dedicated Session Required** Okay, so I've dissected this patch for `drivers/vhost/vsock.c` pretty thoroughly. The initial check pointed out that the `vhost_transport.seqpacket_max_size` wasn't set, and that if it *was* set, there's a size check in `af_vsock.c` to ensure data isn't oversized. The real question is whether this warrants a KMSAN fuzzing session. Let's be clear; if standard KASAN, LOCKDEP, or other standard bug detectors can catch the issue, there's no need to spin up KMSAN, which is costly. I see that this patch adds a `seqpacket_max_size` callback to `struct vsock_transport`, implements it in `virtio_transport.c` and `vsock_loopback.c` by way of `virtio_transport_seqpacket_max_size`. This function then calls `virtio_transport_tx_buf_size`, which is protected by a spin lock. In `af_vsock.c`, they're introducing a new `min_space` variable, that's either the length of the message - written bytes, or 1. The crucial part is identifying if we're dealing with uninitialized memory. Let's go through the variables. `min_space` is *always* assigned a value, depending on the socket type, the `max_size` used in the seqpacket check is initialized via `virtio_transport_tx_buf_size` so there are no uninitialized variables. Now, does this touch any memory that gets sent to userspace? No, this is all happening in the `sendmsg` path from user space, and doesn't change anything about how we're copying data. It's really just about controlling the data enqueuing. No changes to buffer lengths or allocations, no user-space copies, no uninitialized memory exposure. I checked for deadlocks or infinite loops. No. Now, going through the criteria for needing KMSAN: 1. Kernel structures sent to userspace: Nope. 2. Conditional logic with uninitialized variables: Nope, all are initialized. 3. Complex data structure initialization: Nope. 4. Bounds checks that could expose uninitialized data: Nope. Since this patch mainly deals with flow control for seqpacket sockets and adds a function for buffer size, with all variables initialized before use, standard sanitizers are enough. No KMSAN is needed. I've reviewed all the details. This patch implements a flow control mechanism for `SOCK_SEQPACKET` which prevents corrupt sequence boundaries and introduces a buffer size query function. All variables are initialized before use and no uninitialized memory risks or kernel-to-user memory operations are introduced. So, the verdict: `NeedsKMSAN = false`. I'm ready to move on. |
| 46/3 | 2026/09/21 11:09 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch introduces flow-control improvements for SOCK_SEQPACKET in AF_VSOCK (virtio transport). Specifically, it ensures that SEQPACKET messages wait until sufficient space is available (min_space = len - total_written) before enqueueing, and rejects oversized messages up-front via a new transport callback (`seqpacket_max_size`).\n\nNo uninitialized memory hazards are introduced or exposed:\n1. All newly introduced local variables (`min_space`, `max_size`) are deterministically initialized in all execution branches prior to being read.\n2. No data is copied to user space; the modified path is in the send/transmit path (`vsock_connectible_sendmsg`), moving data from user space into socket buffers.\n3. No kernel heap/stack buffers or structure paddings that could be read or leaked are modified or allocated.\n4. Surrounding buffer bounds and data access logic remain strictly bounded by user-supplied lengths.\n\nAny potential issues arising from this patch (such as deadlocks, lock contention around `tx_lock`, or socket reference handling) fall entirely under LOCKDEP, KASAN, or standard kernel bug detection mechanisms. Thus, a dedicated KMSAN fuzzing session is not justified.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch introduces flow-control improvements for SOCK_SEQPACKET in AF_VSOCK (virtio transport). Specifically, it ensures that SEQPACKET messages wait until sufficient space is available (min_space = len - total_written) before enqueueing, and rejects oversized messages up-front via a new transport callback (`seqpacket_max_size`).\n\nNo uninitialized memory hazards are introduced or exposed:\n1. All newly introduced local variables (`min_space`, `max_size`) are deterministically initialized in all execution branches prior to being read.\n2. No data is copied to user space; the modified path is in the send/transmit path (`vsock_connectible_sendmsg`), moving data from user space into socket buffers.\n3. No kernel heap/stack buffers or structure paddings that could be read or leaked are modified or allocated.\n4. Surrounding buffer bounds and data access logic remain strictly bounded by user-supplied lengths.\n\nAny potential issues arising from this patch (such as deadlocks, lock contention around `tx_lock`, or socket reference handling) fall entirely under LOCKDEP, KASAN, or standard kernel bug detection mechanisms. Thus, a dedicated KMSAN fuzzing session is not justified.",
"NeedsKMSAN": false
} |
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| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
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