AI Trajectory

null

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK",
    "VIRTIO_VSOCKETS"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_insert_connected"
  ],
  "KMSANReasoning": "The patch adds a boolean flag `ever_connected` to `struct vsock_sock` to track if a vsock socket has ever been connected. This flag is used in `vsock_connect()` to prevent resetting the socket state to `TCP_CLOSE` and `SS_UNCONNECTED` if it was previously connected, fixing a potential race condition or insecure state transition. The `struct vsock_sock` is allocated using `sk_alloc()`, which zeroes the allocated memory, ensuring that `ever_connected` is properly initialized to `false`. The changes do not introduce any new allocations of complex structures, do not copy kernel memory to user space, and do not alter bounds checking in a way that could expose uninitialized memory. Any bugs related to this state transition (e.g., race conditions leading to Use-After-Free or memory corruption) would be caught by KASAN or LOCKDEP. KMSAN is specifically designed to detect uninitialized memory reads and info-leaks, which are not a risk introduced by this patch. Therefore, a dedicated KMSAN fuzzing session is not necessary.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies the core vsock connection logic in `vsock_connect()` and `vsock_insert_connected()` to fix a race condition by introducing a new `ever_connected` boolean flag. This is a functional change in reachable core kernel networking code that affects connection state handling and error paths.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit d4f10b7a3afc7504c00bd5a5ed06a5af5de86b47\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Aug 12 21:46:28 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/include/net/af_vsock.h b/include/net/af_vsock.h\nindex 30046a3c20f73..d7ec976ed6e27 100644\n--- a/include/net/af_vsock.h\n+++ b/include/net/af_vsock.h\n@@ -63,6 +63,8 @@ struct vsock_sock {\n \tstruct delayed_work pending_work;\n \tstruct delayed_work close_work;\n \tbool close_work_scheduled;\n+\t/* Set once the connection completed; never cleared. */\n+\tbool ever_connected;\n \tu32 peer_shutdown;\n \tbool sent_request;\n \tbool ignore_connecting_rst;\ndiff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c\nindex 622dbd0467994..735c91bb76224 100644\n--- a/net/vmw_vsock/af_vsock.c\n+++ b/net/vmw_vsock/af_vsock.c\n@@ -351,6 +351,8 @@ void vsock_insert_connected(struct vsock_sock *vsk)\n \tstruct list_head *list = vsock_connected_sockets(\n \t\t\u0026vsk-\u003eremote_addr, \u0026vsk-\u003elocal_addr);\n \n+\tvsk-\u003eever_connected = true;\n+\n \tspin_lock_bh(\u0026vsock_table_lock);\n \t__vsock_insert_connected(list, vsk);\n \tspin_unlock_bh(\u0026vsock_table_lock);\n@@ -1814,14 +1816,14 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\n \t\t * Note that allowing to \"reset\" an already established socket\n \t\t * here is racy and insecure.\n \t\t */\n-\t\tif (sk-\u003esk_state == TCP_ESTABLISHED)\n+\t\tif (vsk-\u003eever_connected)\n \t\t\tbreak;\n \n \t\t/* If connection was _not_ established and a signal/timeout came\n \t\t * to be, we want the socket's state reset. User space may want\n \t\t * to retry.\n \t\t *\n-\t\t * sk_state != TCP_ESTABLISHED implies that socket is not on\n+\t\t * !ever_connected implies that socket is not on\n \t\t * vsock_connected_table. We keep the binding and the transport\n \t\t * assigned.\n \t\t */\n@@ -1849,8 +1851,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\n \n \tif (sk-\u003esk_err) {\n \t\terr = -sk-\u003esk_err;\n-\t\tsk-\u003esk_state = TCP_CLOSE;\n-\t\tsock-\u003estate = SS_UNCONNECTED;\n+\t\tif (!vsk-\u003eever_connected) {\n+\t\t\tsk-\u003esk_state = TCP_CLOSE;\n+\t\t\tsock-\u003estate = SS_UNCONNECTED;\n+\t\t}\n \t} else {\n \t\terr = 0;\n \t}\n"
}

best-expensive

null

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK",
    "VIRTIO_VSOCKETS"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_insert_connected"
  ],
  "Reasoning": "The patch modifies the core vsock connection logic in `vsock_connect()` and `vsock_insert_connected()` to fix a race condition by introducing a new `ever_connected` boolean flag. This is a functional change in reachable core kernel networking code that affects connection state handling and error paths.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer.
Your job is to review a provided patch series and determine
if it makes functional changes to the kernel that should be fuzzed.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively
use your code access tools to examine the actual source code and confirm any assumptions.

Return WorthFuzzing=false if the patch only contains:
- Modifications to Documentation/, Kconfig files, or code comments.
- Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints.
- Changes to numeric constants or macros that do not functionally alter execution flow.
- Code paths that are impossible to reach in virtualized environments like GCE or QEMU,
  even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim).
- Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed,
  ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU.
- Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove)
  that are executed only during PCI hot-unplug or sysfs driver unbind operations.

If it modifies reachable core kernel logic, drivers, or architectures, use your code search
tools to verify the code can be executed, then return WorthFuzzing=true.

When returning WorthFuzzing=true, you MUST ALSO:
1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols.
   Avoid listing generic hot-path functions to prevent skewed test distributions.
   Prefer non-static, non-inlined API entrypoint functions over internal static helper functions
   (which are inlined by the compiler and do not have distinct symbol addresses).
2. Identify any specific CONFIG_ options required to properly test this new/modified feature.
   Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions.
   Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs
   needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs
   output array, and DO NOT add a '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.

For your convenience, here is the diff of the changes:
commit d4f10b7a3afc7504c00bd5a5ed06a5af5de86b47
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Aug 12 21:46:28 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 30046a3c20f73..d7ec976ed6e27 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -63,6 +63,8 @@ struct vsock_sock {
 	struct delayed_work pending_work;
 	struct delayed_work close_work;
 	bool close_work_scheduled;
+	/* Set once the connection completed; never cleared. */
+	bool ever_connected;
 	u32 peer_shutdown;
 	bool sent_request;
 	bool ignore_connecting_rst;
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 622dbd0467994..735c91bb76224 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -351,6 +351,8 @@ void vsock_insert_connected(struct vsock_sock *vsk)
 	struct list_head *list = vsock_connected_sockets(
 		&vsk->remote_addr, &vsk->local_addr);
 
+	vsk->ever_connected = true;
+
 	spin_lock_bh(&vsock_table_lock);
 	__vsock_insert_connected(list, vsk);
 	spin_unlock_bh(&vsock_table_lock);
@@ -1814,14 +1816,14 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 		 * Note that allowing to "reset" an already established socket
 		 * here is racy and insecure.
 		 */
-		if (sk->sk_state == TCP_ESTABLISHED)
+		if (vsk->ever_connected)
 			break;
 
 		/* If connection was _not_ established and a signal/timeout came
 		 * to be, we want the socket's state reset. User space may want
 		 * to retry.
 		 *
-		 * sk_state != TCP_ESTABLISHED implies that socket is not on
+		 * !ever_connected implies that socket is not on
 		 * vsock_connected_table. We keep the binding and the transport
 		 * assigned.
 		 */
@@ -1849,8 +1851,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 
 	if (sk->sk_err) {
 		err = -sk->sk_err;
-		sk->sk_state = TCP_CLOSE;
-		sock->state = SS_UNCONNECTED;
+		if (!vsk->ever_connected) {
+			sk->sk_state = TCP_CLOSE;
+			sock->state = SS_UNCONNECTED;
+		}
 	} else {
 		err = 0;
 	}

gemini-3.1-pro-preview

null

null

							input: 2570
							output: 34
							thoughts: 216
						

**Analyzing the vsock Connection Logic Patch**

Okay, so this patch is touching `net/vmw_vsock/af_vsock.c` and `include/net/af_vsock.h` – that's the core vsock code. They're adding an `ever_connected` boolean field to the `struct vsock_sock`, which is interesting. It looks like they're tracking connection state more accurately, setting it to `true` in `vsock_insert_connected()`.

The really key part is the change in `vsock_connect()`. It's replacing the standard TCP state check, `sk->sk_state == TCP_ESTABLISHED`, with `vsk->ever_connected`. That suggests they're addressing a subtle race condition or state issue when a vsock socket is connecting. Also, resetting `sk->sk_state` and `sock->state` conditionally based on `!vsk->ever_connected` indicates careful error handling, and avoiding issues for subsequent connection attempts.

This is a fundamental change to the connection handling, not just a cosmetic fix. Because it deals with connection state, and connection handling is so tricky, it definitely opens the door for fuzzing. I'd want to throw a lot of connection/disconnection variations at it to make sure we don't end up with some weird corner case.

Now, I need to figure out what config options control vsock. `net/vmw_vsock/Kconfig` is the obvious place to start. I'm betting that's where I'll find `VSOCKETS`. Let's confirm that.

{
  "Expression": "config VSOCKETS",
  "PathPrefix": "net/vmw_vsock/Kconfig"
}

{
  "Output": "net/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"
}

gemini-3.1-pro-preview

null

null

							input: 3365
							output: 38
							thoughts: 121
						

**My Initial Assessment of the VSOCK Subsystem**

Alright, let's dive into this `VSOCKETS` situation. It's the core configuration, naturally. And, hey, `VSOCKETS_LOOPBACK` looks like a handy tool for local vsock fuzzing without having to fire up a full hypervisor. Saves time, and that's always good.

My immediate focus, given the context, has to be on these key functions: `vsock_connect` and `vsock_insert_connected`. I need to understand how they work.

First order of business: let's see if `vsock_connect` is exported or static. *Ah*, it's static, found in `net/vmw_vsock/af_vsock.c`. That's not ideal, as it limits direct access. So, let's back up a bit, it looks like `vsock_connect` is off the table at first glance, meaning the functions to focus on are `vsock_insert_connected`. Given that `vsock_connect` is static, I should be looking at the related non-static functions for manipulation.

{
  "Expression": "vsock_connect",
  "PathPrefix": "net/vmw_vsock/af_vsock.c"
}

{
  "Output": "net/vmw_vsock/af_vsock.c=212=static DEFINE_MUTEX(vsock_register_mutex);\n--\nnet/vmw_vsock/af_vsock.c-238-\t(((src)-\u003esvm_cid ^ (dst)-\u003esvm_port) % VSOCK_HASH_SIZE)\nnet/vmw_vsock/af_vsock.c:239:#define vsock_connected_sockets(src, dst)\t\t\\\nnet/vmw_vsock/af_vsock.c:240:\t(\u0026vsock_connected_table[VSOCK_CONN_HASH(src, dst)])\nnet/vmw_vsock/af_vsock.c:241:#define vsock_connected_sockets_vsk(vsk)\t\t\t\t\\\nnet/vmw_vsock/af_vsock.c:242:\tvsock_connected_sockets(\u0026(vsk)-\u003eremote_addr, \u0026(vsk)-\u003elocal_addr)\nnet/vmw_vsock/af_vsock.c-243-\n--\nnet/vmw_vsock/af_vsock.c=245=EXPORT_SYMBOL_GPL(vsock_bind_table);\nnet/vmw_vsock/af_vsock.c:246:struct list_head vsock_connected_table[VSOCK_HASH_SIZE];\nnet/vmw_vsock/af_vsock.c:247:EXPORT_SYMBOL_GPL(vsock_connected_table);\nnet/vmw_vsock/af_vsock.c-248-DEFINE_SPINLOCK(vsock_table_lock);\n--\nnet/vmw_vsock/af_vsock.c=263=static void vsock_init_tables(void)\n--\nnet/vmw_vsock/af_vsock.c-269-\nnet/vmw_vsock/af_vsock.c:270:\tfor (i = 0; i \u003c ARRAY_SIZE(vsock_connected_table); i++)\nnet/vmw_vsock/af_vsock.c:271:\t\tINIT_LIST_HEAD(\u0026vsock_connected_table[i]);\nnet/vmw_vsock/af_vsock.c-272-}\n--\nnet/vmw_vsock/af_vsock.c=323=__vsock_find_connected_socket_net(struct sockaddr_vm *src,\n--\nnet/vmw_vsock/af_vsock.c-327-\nnet/vmw_vsock/af_vsock.c:328:\tlist_for_each_entry(vsk, vsock_connected_sockets(src, dst),\nnet/vmw_vsock/af_vsock.c-329-\t\t\t    connected_table) {\n--\nnet/vmw_vsock/af_vsock.c=349=void vsock_insert_connected(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-350-{\nnet/vmw_vsock/af_vsock.c:351:\tstruct list_head *list = vsock_connected_sockets(\nnet/vmw_vsock/af_vsock.c-352-\t\t\u0026vsk-\u003eremote_addr, \u0026vsk-\u003elocal_addr);\n--\nnet/vmw_vsock/af_vsock.c=456=void vsock_for_each_connected_socket(struct vsock_transport *transport,\n--\nnet/vmw_vsock/af_vsock.c-462-\nnet/vmw_vsock/af_vsock.c:463:\tfor (i = 0; i \u003c ARRAY_SIZE(vsock_connected_table); i++) {\nnet/vmw_vsock/af_vsock.c-464-\t\tstruct vsock_sock *vsk;\nnet/vmw_vsock/af_vsock.c:465:\t\tlist_for_each_entry(vsk, \u0026vsock_connected_table[i],\nnet/vmw_vsock/af_vsock.c-466-\t\t\t\t    connected_table) {\n--\nnet/vmw_vsock/af_vsock.c=572=int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)\n--\nnet/vmw_vsock/af_vsock.c-645-\t\t/* transport-\u003erelease() must be called with sock lock acquired.\nnet/vmw_vsock/af_vsock.c:646:\t\t * This path can only be taken during vsock_connect(), where we\nnet/vmw_vsock/af_vsock.c-647-\t\t * have already held the sock lock. In the other cases, this\n--\nnet/vmw_vsock/af_vsock.c-655-\t\t * state, since we are reassigning the socket to a new transport\nnet/vmw_vsock/af_vsock.c:656:\t\t * during vsock_connect(), let's reset these fields to have a\nnet/vmw_vsock/af_vsock.c-657-\t\t * clean state.\n--\nnet/vmw_vsock/af_vsock.c=871=static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)\n--\nnet/vmw_vsock/af_vsock.c-907-\nnet/vmw_vsock/af_vsock.c:908:static void vsock_connect_timeout(struct work_struct *work);\nnet/vmw_vsock/af_vsock.c-909-\nnet/vmw_vsock/af_vsock.c=910=static struct sock *__vsock_create(struct net *net,\n--\nnet/vmw_vsock/af_vsock.c-950-\tWRITE_ONCE(vsk-\u003epeer_shutdown, 0);\nnet/vmw_vsock/af_vsock.c:951:\tINIT_DELAYED_WORK(\u0026vsk-\u003econnect_work, vsock_connect_timeout);\nnet/vmw_vsock/af_vsock.c-952-\tINIT_DELAYED_WORK(\u0026vsk-\u003epending_work, vsock_pending_work);\n--\nnet/vmw_vsock/af_vsock.c=1065=EXPORT_SYMBOL_GPL(vsock_stream_has_data);\nnet/vmw_vsock/af_vsock.c-1066-\nnet/vmw_vsock/af_vsock.c:1067:s64 vsock_connectible_has_data(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-1068-{\n--\nnet/vmw_vsock/af_vsock.c-1078-}\nnet/vmw_vsock/af_vsock.c:1079:EXPORT_SYMBOL_GPL(vsock_connectible_has_data);\nnet/vmw_vsock/af_vsock.c-1080-\n--\nnet/vmw_vsock/af_vsock.c=1647=static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/af_vsock.c-1656-\nnet/vmw_vsock/af_vsock.c:1657:static void vsock_connect_timeout(struct work_struct *work)\nnet/vmw_vsock/af_vsock.c-1658-{\n--\nnet/vmw_vsock/af_vsock.c-1678-\nnet/vmw_vsock/af_vsock.c:1679:static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\nnet/vmw_vsock/af_vsock.c-1680-\t\t\t int addr_len, int flags)\n--\nnet/vmw_vsock/af_vsock.c-1826-\t\t * !ever_connected implies that socket is not on\nnet/vmw_vsock/af_vsock.c:1827:\t\t * vsock_connected_table. We keep the binding and the transport\nnet/vmw_vsock/af_vsock.c-1828-\t\t * assigned.\n--\nnet/vmw_vsock/af_vsock.c=1992=static void vsock_update_buffer_size(struct vsock_sock *vsk,\n--\nnet/vmw_vsock/af_vsock.c-2008-\nnet/vmw_vsock/af_vsock.c:2009:static int vsock_connectible_setsockopt(struct socket *sock,\nnet/vmw_vsock/af_vsock.c-2010-\t\t\t\t\tint level,\n--\nnet/vmw_vsock/af_vsock.c-2122-\nnet/vmw_vsock/af_vsock.c:2123:static int vsock_connectible_getsockopt(struct socket *sock,\nnet/vmw_vsock/af_vsock.c-2124-\t\t\t\t\tint level, int optname,\n--\nnet/vmw_vsock/af_vsock.c-2181-\nnet/vmw_vsock/af_vsock.c:2182:static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,\nnet/vmw_vsock/af_vsock.c-2183-\t\t\t\t     size_t len)\n--\nnet/vmw_vsock/af_vsock.c-2343-\nnet/vmw_vsock/af_vsock.c:2344:static int vsock_connectible_wait_data(struct sock *sk,\nnet/vmw_vsock/af_vsock.c-2345-\t\t\t\t       struct wait_queue_entry *wait,\n--\nnet/vmw_vsock/af_vsock.c-2360-\t\tprepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);\nnet/vmw_vsock/af_vsock.c:2361:\t\tdata = vsock_connectible_has_data(vsk);\nnet/vmw_vsock/af_vsock.c-2362-\t\tif (data != 0)\n--\nnet/vmw_vsock/af_vsock.c=2411=static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2448-\nnet/vmw_vsock/af_vsock.c:2449:\t\terr = vsock_connectible_wait_data(sk, \u0026wait, timeout,\nnet/vmw_vsock/af_vsock.c-2450-\t\t\t\t\t\t  \u0026recv_data, target);\n--\nnet/vmw_vsock/af_vsock.c=2490=static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,\n--\nnet/vmw_vsock/af_vsock.c-2504-\nnet/vmw_vsock/af_vsock.c:2505:\terr = vsock_connectible_wait_data(sk, \u0026wait, timeout, NULL, 0);\nnet/vmw_vsock/af_vsock.c-2506-\tif (err \u003c= 0)\n--\nnet/vmw_vsock/af_vsock.c=2540=int\nnet/vmw_vsock/af_vsock.c:2541:__vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,\nnet/vmw_vsock/af_vsock.c-2542-\t\t\t    int flags)\n--\nnet/vmw_vsock/af_vsock.c=2607=int\nnet/vmw_vsock/af_vsock.c:2608:vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,\nnet/vmw_vsock/af_vsock.c-2609-\t\t\t  int flags)\n--\nnet/vmw_vsock/af_vsock.c-2619-\nnet/vmw_vsock/af_vsock.c:2620:\treturn __vsock_connectible_recvmsg(sock, msg, len, flags);\nnet/vmw_vsock/af_vsock.c-2621-}\nnet/vmw_vsock/af_vsock.c:2622:EXPORT_SYMBOL_GPL(vsock_connectible_recvmsg);\nnet/vmw_vsock/af_vsock.c-2623-\n--\nnet/vmw_vsock/af_vsock.c=2648=static const struct proto_ops vsock_stream_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2652-\t.bind = vsock_bind,\nnet/vmw_vsock/af_vsock.c:2653:\t.connect = vsock_connect,\nnet/vmw_vsock/af_vsock.c-2654-\t.socketpair = sock_no_socketpair,\n--\nnet/vmw_vsock/af_vsock.c-2660-\t.shutdown = vsock_shutdown,\nnet/vmw_vsock/af_vsock.c:2661:\t.setsockopt = vsock_connectible_setsockopt,\nnet/vmw_vsock/af_vsock.c:2662:\t.getsockopt_iter = vsock_connectible_getsockopt,\nnet/vmw_vsock/af_vsock.c:2663:\t.sendmsg = vsock_connectible_sendmsg,\nnet/vmw_vsock/af_vsock.c:2664:\t.recvmsg = vsock_connectible_recvmsg,\nnet/vmw_vsock/af_vsock.c-2665-\t.mmap = sock_no_mmap,\n--\nnet/vmw_vsock/af_vsock.c=2670=static const struct proto_ops vsock_seqpacket_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2674-\t.bind = vsock_bind,\nnet/vmw_vsock/af_vsock.c:2675:\t.connect = vsock_connect,\nnet/vmw_vsock/af_vsock.c-2676-\t.socketpair = sock_no_socketpair,\n--\nnet/vmw_vsock/af_vsock.c-2682-\t.shutdown = vsock_shutdown,\nnet/vmw_vsock/af_vsock.c:2683:\t.setsockopt = vsock_connectible_setsockopt,\nnet/vmw_vsock/af_vsock.c:2684:\t.getsockopt_iter = vsock_connectible_getsockopt,\nnet/vmw_vsock/af_vsock.c:2685:\t.sendmsg = vsock_connectible_sendmsg,\nnet/vmw_vsock/af_vsock.c:2686:\t.recvmsg = vsock_connectible_recvmsg,\nnet/vmw_vsock/af_vsock.c-2687-\t.mmap = sock_no_mmap,\n"
}

gemini-3.1-pro-preview

null

null

							input: 7682
							output: 40
							thoughts: 93
						

**My Analysis of VSock Connection Handling**

Okay, so I'm looking at the vsock implementation, and I see something interesting with `vsock_connect`. It's defined statically, but it's clearly the function that handles the `connect()` syscall for the vsock protocol, since it's assigned to `.connect` within both `vsock_stream_ops` and `vsock_seqpacket_ops`. This makes perfect sense; `connect` is the standard way to establish a connection.

Now, I've got to understand how connections are established and managed, so I'm going to dig into `vsock_insert_connected`. Fortunately, it's exported, so I can track where this happens. It's the key to tracking down what happens after a connection is initiated. I need to understand what happens with the socket state transitions and data structures after the `connect` syscall. I'll head over to `net/vmw_vsock/af_vsock.c` to examine this function and how it fits into the broader connection workflow.

{
  "Expression": "vsock_insert_connected",
  "PathPrefix": "net/vmw_vsock/af_vsock.c"
}

{
  "Output": "net/vmw_vsock/af_vsock.c=274=static void __vsock_insert_bound(struct list_head *list,\n--\nnet/vmw_vsock/af_vsock.c-280-\nnet/vmw_vsock/af_vsock.c:281:static void __vsock_insert_connected(struct list_head *list,\nnet/vmw_vsock/af_vsock.c-282-\t\t\t\t     struct vsock_sock *vsk)\n--\nnet/vmw_vsock/af_vsock.c=342=static void vsock_insert_unbound(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/af_vsock.c-348-\nnet/vmw_vsock/af_vsock.c:349:void vsock_insert_connected(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-350-{\n--\nnet/vmw_vsock/af_vsock.c-356-\tspin_lock_bh(\u0026vsock_table_lock);\nnet/vmw_vsock/af_vsock.c:357:\t__vsock_insert_connected(list, vsk);\nnet/vmw_vsock/af_vsock.c-358-\tspin_unlock_bh(\u0026vsock_table_lock);\nnet/vmw_vsock/af_vsock.c-359-}\nnet/vmw_vsock/af_vsock.c:360:EXPORT_SYMBOL_GPL(vsock_insert_connected);\nnet/vmw_vsock/af_vsock.c-361-\n"
}

gemini-3.1-pro-preview

null

null

							input: 8480
							output: 34
							thoughts: 29
						

Okay, here's my take on those thoughts, framed as if they're my own:

**Investigating vsock_insert_connected**

Right, so `vsock_insert_connected` is exported, meaning it's intended for external use. I need to understand its context and how it's being leveraged within the system. My next logical step is to trace its usage. I'll need to locate all the places in the codebase where `vsock_insert_connected` is actually *called*. That's where the interesting stuff will be, revealing how connections are being established and managed within the vsock framework. Finding those call sites will be key to understanding the workflow.

{
  "Expression": "vsock_insert_connected",
  "PathPrefix": "net/vmw_vsock/"
}

{
  "Output": "net/vmw_vsock/af_vsock.c=274=static void __vsock_insert_bound(struct list_head *list,\n--\nnet/vmw_vsock/af_vsock.c-280-\nnet/vmw_vsock/af_vsock.c:281:static void __vsock_insert_connected(struct list_head *list,\nnet/vmw_vsock/af_vsock.c-282-\t\t\t\t     struct vsock_sock *vsk)\n--\nnet/vmw_vsock/af_vsock.c=342=static void vsock_insert_unbound(struct vsock_sock *vsk)\n--\nnet/vmw_vsock/af_vsock.c-348-\nnet/vmw_vsock/af_vsock.c:349:void vsock_insert_connected(struct vsock_sock *vsk)\nnet/vmw_vsock/af_vsock.c-350-{\n--\nnet/vmw_vsock/af_vsock.c-356-\tspin_lock_bh(\u0026vsock_table_lock);\nnet/vmw_vsock/af_vsock.c:357:\t__vsock_insert_connected(list, vsk);\nnet/vmw_vsock/af_vsock.c-358-\tspin_unlock_bh(\u0026vsock_table_lock);\nnet/vmw_vsock/af_vsock.c-359-}\nnet/vmw_vsock/af_vsock.c:360:EXPORT_SYMBOL_GPL(vsock_insert_connected);\nnet/vmw_vsock/af_vsock.c-361-\n--\nnet/vmw_vsock/hyperv_transport.c=295=static void hvs_open_connection(struct vmbus_channel *chan)\n--\nnet/vmw_vsock/hyperv_transport.c-416-\nnet/vmw_vsock/hyperv_transport.c:417:\t\tvsock_insert_connected(vnew);\nnet/vmw_vsock/hyperv_transport.c-418-\n--\nnet/vmw_vsock/hyperv_transport.c-423-\nnet/vmw_vsock/hyperv_transport.c:424:\t\tvsock_insert_connected(vsock_sk(sk));\nnet/vmw_vsock/hyperv_transport.c-425-\t}\n--\nnet/vmw_vsock/virtio_transport_common.c=1461=virtio_transport_recv_connecting(struct sock *sk,\n--\nnet/vmw_vsock/virtio_transport_common.c-1472-\t\tsk-\u003esk_socket-\u003estate = SS_CONNECTED;\nnet/vmw_vsock/virtio_transport_common.c:1473:\t\tvsock_insert_connected(vsk);\nnet/vmw_vsock/virtio_transport_common.c-1474-\t\tsk-\u003esk_state_change(sk);\n--\nnet/vmw_vsock/virtio_transport_common.c=1694=virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,\n--\nnet/vmw_vsock/virtio_transport_common.c-1750-\nnet/vmw_vsock/virtio_transport_common.c:1751:\tvsock_insert_connected(vchild);\nnet/vmw_vsock/virtio_transport_common.c-1752-\tvsock_enqueue_accept(sk, child);\n--\nnet/vmw_vsock/vmci_transport.c=1137=vmci_transport_recv_connecting_server(struct sock *listener,\n--\nnet/vmw_vsock/vmci_transport.c-1240-\nnet/vmw_vsock/vmci_transport.c:1241:\tvsock_insert_connected(vpending);\nnet/vmw_vsock/vmci_transport.c-1242-\n--\nnet/vmw_vsock/vmci_transport.c=1283=vmci_transport_recv_connecting_client(struct sock *sk,\n--\nnet/vmw_vsock/vmci_transport.c-1308-\t\tsk-\u003esk_socket-\u003estate = SS_CONNECTED;\nnet/vmw_vsock/vmci_transport.c:1309:\t\tvsock_insert_connected(vsk);\nnet/vmw_vsock/vmci_transport.c-1310-\t\tsk-\u003esk_state_change(sk);\n"
}

gemini-3.1-pro-preview

null

null

							input: 9857
							output: 38
							thoughts: 153
						

**My Current Analysis of the vsock Connection Fix**

Okay, so I'm looking at this `vsock_insert_connected` function. It seems this is the critical point where the transports are acknowledging a connection has been successfully established. The fix in this patch immediately jumps out because of that race condition: the previous check of `sk->sk_state == TCP_ESTABLISHED` within `vsock_connect` was flawed and vulnerable. It seems the issue was relying on a state transition that wasn't reliably indicating connection success. Now, they're correctly leveraging `vsk->ever_connected`, which is set precisely within `vsock_insert_connected`. This makes a lot more sense, and avoids the race.

The next step is fuzzing, which means I need to design test cases around vsock connections. Naturally, I’ll need the `VSOCKETS` and `VSOCKETS_LOOPBACK` configurations enabled to support that. Ah, but what about `VIRTIO_VSOCKETS`? I should probably confirm that isn't a factor here. Let's quickly review the `net/vmw_vsock/Kconfig` file. I'll need to make sure I'm taking all available options into account.

{
  "Expression": "config VIRTIO_VSOCKETS",
  "PathPrefix": "net/vmw_vsock/Kconfig"
}

{
  "Output": "net/vmw_vsock/Kconfig=41=config VMWARE_VMCI_VSOCKETS\n--\nnet/vmw_vsock/Kconfig-52-\nnet/vmw_vsock/Kconfig:53:config VIRTIO_VSOCKETS\nnet/vmw_vsock/Kconfig-54-\ttristate \"virtio transport for Virtual Sockets\"\n--\nnet/vmw_vsock/Kconfig-65-\nnet/vmw_vsock/Kconfig:66:config VIRTIO_VSOCKETS_COMMON\nnet/vmw_vsock/Kconfig-67-\ttristate\n"
}

gemini-3.1-pro-preview

null

null

							input: 10478
							output: 37
							thoughts: 48
						

Okay, here's my take on those thoughts, framed as my own:

**Digging into Virtual Sockets**

Right, let's see, while I'm looking at VIRTIO network devices I need to keep in mind VIRTIO_VSOCKETS and VIRTIO_VSOCKETS_COMMON. Those are important, I believe they are related to the virtual socket functionality. I'll need to remember them.

To get a handle on the available configuration options for these VIRTIO sockets, the most logical place to start is the Kconfig file in the `net/vmw_vsock/` directory, I should check there. That should contain all the relevant configuration options. That will give me a clear picture of what's supported and configurable.

{
  "File": "net/vmw_vsock/Kconfig",
  "FirstLine": 1,
  "LineCount": 100
}

{
  "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  81:\t\n  82:\t\t  To compile this driver as a module, choose M here: the module will be\n  83:\t\t  called hv_sock. If unsure, say N.\n"
}

gemini-3.1-pro-preview

null

null

							input: 11847
							output: 132
							thoughts: 434
						

**My Analysis of the Vsock Patch**

Okay, so I've been looking at this vsock patch, and the key configurations to enable seem to be `VSOCKETS`, `VSOCKETS_LOOPBACK`, and `VIRTIO_VSOCKETS`. That seems straightforward. Now, the meat of this is about those function calls.

Initially, I was hesitant about `vsock_connect` because it's marked as `static`. I know the general principle is to prioritize non-static, non-inlined entrypoints for fuzzing. We want symbols that syzkaller can readily target. But, wait, a closer look shows `vsock_connect` is assigned to a function pointer within `proto_ops`. That means the compiler *can't* inline it, so despite the `static` declaration, it's a valid candidate. The prompt specifically noted that even static functions are okay if not inlined and passed as a function pointer. I'll definitely include that one.

Then, there's `vsock_insert_connected`, which *is* exported and should be a good target as well. I need to make sure I get both. Let's make sure that `vsock_connect` is definitively not inlined. Yep, it is passed as a function pointer, confirming that it is not inlined.

I glanced over other functions, but the patch seems focused squarely on modifications to `vsock_connect` and `vsock_insert_connected`. Other functions like `vsock_assign_transport` haven't been touched in this change.

Essentially, this patch is addressing a race condition in the vsock connection logic by introducing an `ever_connected` flag. This alters the connection state handling and potential error paths within the core kernel networking code, which is relevant and very impactful. So, `vsock_connect` and `vsock_insert_connected` are the key functions I'm going to focus on.

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK",
    "VIRTIO_VSOCKETS"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_insert_connected"
  ],
  "Reasoning": "The patch modifies the core vsock connection logic in `vsock_connect()` and `vsock_insert_connected()` to fix a race condition by introducing a new `ever_connected` boolean flag. This is a functional change in reachable core kernel networking code that affects connection state handling and error paths.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK",
    "VIRTIO_VSOCKETS"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_insert_connected"
  ],
  "Reasoning": "The patch modifies the core vsock connection logic in `vsock_connect()` and `vsock_insert_connected()` to fix a race condition by introducing a new `ever_connected` boolean flag. This is a functional change in reachable core kernel networking code that affects connection state handling and error paths.",
  "WorthFuzzing": true
}

{
  "WorthFuzzing": true
}

null

best-expensive

null

{
  "KMSANReasoning": "The patch adds a boolean flag `ever_connected` to `struct vsock_sock` to track if a vsock socket has ever been connected. This flag is used in `vsock_connect()` to prevent resetting the socket state to `TCP_CLOSE` and `SS_UNCONNECTED` if it was previously connected, fixing a potential race condition or insecure state transition. The `struct vsock_sock` is allocated using `sk_alloc()`, which zeroes the allocated memory, ensuring that `ever_connected` is properly initialized to `false`. The changes do not introduce any new allocations of complex structures, do not copy kernel memory to user space, and do not alter bounds checking in a way that could expose uninitialized memory. Any bugs related to this state transition (e.g., race conditions leading to Use-After-Free or memory corruption) would be caught by KASAN or LOCKDEP. KMSAN is specifically designed to detect uninitialized memory reads and info-leaks, which are not a risk introduced by this patch. Therefore, a dedicated KMSAN fuzzing session is not necessary.",
  "NeedsKMSAN": false
}

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.

For your convenience, here is the diff of the changes:
commit d4f10b7a3afc7504c00bd5a5ed06a5af5de86b47
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Aug 12 21:46:28 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 30046a3c20f73..d7ec976ed6e27 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -63,6 +63,8 @@ struct vsock_sock {
 	struct delayed_work pending_work;
 	struct delayed_work close_work;
 	bool close_work_scheduled;
+	/* Set once the connection completed; never cleared. */
+	bool ever_connected;
 	u32 peer_shutdown;
 	bool sent_request;
 	bool ignore_connecting_rst;
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 622dbd0467994..735c91bb76224 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -351,6 +351,8 @@ void vsock_insert_connected(struct vsock_sock *vsk)
 	struct list_head *list = vsock_connected_sockets(
 		&vsk->remote_addr, &vsk->local_addr);
 
+	vsk->ever_connected = true;
+
 	spin_lock_bh(&vsock_table_lock);
 	__vsock_insert_connected(list, vsk);
 	spin_unlock_bh(&vsock_table_lock);
@@ -1814,14 +1816,14 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 		 * Note that allowing to "reset" an already established socket
 		 * here is racy and insecure.
 		 */
-		if (sk->sk_state == TCP_ESTABLISHED)
+		if (vsk->ever_connected)
 			break;
 
 		/* If connection was _not_ established and a signal/timeout came
 		 * to be, we want the socket's state reset. User space may want
 		 * to retry.
 		 *
-		 * sk_state != TCP_ESTABLISHED implies that socket is not on
+		 * !ever_connected implies that socket is not on
 		 * vsock_connected_table. We keep the binding and the transport
 		 * assigned.
 		 */
@@ -1849,8 +1851,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 
 	if (sk->sk_err) {
 		err = -sk->sk_err;
-		sk->sk_state = TCP_CLOSE;
-		sock->state = SS_UNCONNECTED;
+		if (!vsk->ever_connected) {
+			sk->sk_state = TCP_CLOSE;
+			sock->state = SS_UNCONNECTED;
+		}
 	} else {
 		err = 0;
 	}

gemini-3.1-pro-preview

null

null

							input: 2567
							output: 37
							thoughts: 420
						

**Analyzing the vsock Connection State Patch**

Okay, so this patch is tweaking the vsock connection logic, specifically around socket state transitions. My immediate thought is, "Does this introduce any uninitialized memory risks?" We're adding a boolean, `ever_connected`, to the `vsock_sock` struct. The patch sets it to `true` in `vsock_insert_connected()`, so that's good. But how is it initialized by default?

I need to confirm that `ever_connected` isn't going to be read without being initialized. It looks like `struct vsock_sock` is allocated via `sk_alloc()`. Ah, right, `sk_alloc()` *should* zero the memory if `sk_prot->obj_size` is set correctly, or `vsock_create()` gets called, which in turn calls `sk_alloc()`. The code flow zeroes the memory using slab.

Let's double-check how `sk_alloc()` works, and `vsock_create()`. Does `sk_alloc` use the slab? Yes, it uses slab and zero the struct. If `SLAB_TYPESAFE_BY_RCU` isn't used, the struct is zeroed. Okay, so we're safe there. I can see from the patch that the check is being changed from `sk->sk_state == TCP_ESTABLISHED` to `vsk->ever_connected` and also using it to prevent resetting the socket.

Okay, so no uninitialized memory read as far as I can tell. It looks like the patch just changes the conditional state check. No data is copied to user space, no complex data structures are allocated, and no bounds checks are modified.

I should double-check `sk_alloc` and `vsock_create()` just to be absolutely sure. Let's use `default_api:grepper` to search for `vsock_create` and `sk_alloc` in the codebase and confirm the zeroing behavior. Seems like this is a solid patch.

{
  "Expression": "sk_alloc",
  "PathPrefix": "net/vmw_vsock/af_vsock.c"
}

{
  "Output": "net/vmw_vsock/af_vsock.c=910=static struct sock *__vsock_create(struct net *net,\n--\nnet/vmw_vsock/af_vsock.c-920-\nnet/vmw_vsock/af_vsock.c:921:\tsk = sk_alloc(net, AF_VSOCK, priority, \u0026vsock_proto, kern);\nnet/vmw_vsock/af_vsock.c-922-\tif (!sk)\n"
}

gemini-3.1-pro-preview

null

null

							input: 3600
							output: 253
							thoughts: 395
						

**My Assessment of the KMSAN Need in This Patch**

Okay, let's break this down. We have a patch that's dealing with socket state transitions in vsock. The core of it seems to be adding a boolean flag, `ever_connected`, to the `vsock_sock` struct to correctly track if a socket has ever been established. This prevents an inappropriate reset to `TCP_CLOSE` and `SS_UNCONNECTED` in `vsock_connect()` after a disconnection or error, which is clearly addressing a potential race condition or security vulnerability, which could be exploited.

Now, the important part for KMSAN: the memory for the `vsock_sock` struct, including `ever_connected`, is allocated with `sk_alloc()`. *That's critical*. `sk_alloc()` zeroes the memory, which means `ever_connected` is *guaranteed* to be initialized to `false` from the start. We're not dealing with uninitialized memory here; the flag is explicitly set to a known state.

The fix isn't about uninitialized reads or memory leaks; it's a logic error, a state management issue.  Even if this state management introduces problems (like, say, a Use-After-Free due to a race), those will be caught by KASAN or potentially LOCKDEP, which we have in place for that. KMSAN's strength is *uninitialized memory*, which is simply not a concern here. This isn't a case for needing a dedicated KMSAN fuzzing campaign. This is a straightforward logic bug fix that's been carefully implemented. Therefore, it does not require a `NeedsKMSAN` tag.

{
  "KMSANReasoning": "The patch adds a boolean flag `ever_connected` to `struct vsock_sock` to track if a vsock socket has ever been connected. This flag is used in `vsock_connect()` to prevent resetting the socket state to `TCP_CLOSE` and `SS_UNCONNECTED` if it was previously connected, fixing a potential race condition or insecure state transition. The `struct vsock_sock` is allocated using `sk_alloc()`, which zeroes the allocated memory, ensuring that `ever_connected` is properly initialized to `false`. The changes do not introduce any new allocations of complex structures, do not copy kernel memory to user space, and do not alter bounds checking in a way that could expose uninitialized memory. Any bugs related to this state transition (e.g., race conditions leading to Use-After-Free or memory corruption) would be caught by KASAN or LOCKDEP. KMSAN is specifically designed to detect uninitialized memory reads and info-leaks, which are not a risk introduced by this patch. Therefore, a dedicated KMSAN fuzzing session is not necessary.",
  "NeedsKMSAN": false
}

{
  "KMSANReasoning": "The patch adds a boolean flag `ever_connected` to `struct vsock_sock` to track if a vsock socket has ever been connected. This flag is used in `vsock_connect()` to prevent resetting the socket state to `TCP_CLOSE` and `SS_UNCONNECTED` if it was previously connected, fixing a potential race condition or insecure state transition. The `struct vsock_sock` is allocated using `sk_alloc()`, which zeroes the allocated memory, ensuring that `ever_connected` is properly initialized to `false`. The changes do not introduce any new allocations of complex structures, do not copy kernel memory to user space, and do not alter bounds checking in a way that could expose uninitialized memory. Any bugs related to this state transition (e.g., race conditions leading to Use-After-Free or memory corruption) would be caught by KASAN or LOCKDEP. KMSAN is specifically designed to detect uninitialized memory reads and info-leaks, which are not a risk introduced by this patch. Therefore, a dedicated KMSAN fuzzing session is not necessary.",
  "NeedsKMSAN": false
}