AI Trajectory

null

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_accept",
    "vsock_pending_work"
  ],
  "KMSANReasoning": "The patch removes the `rejected` field from `struct vsock_sock` and simplifies the error handling in `vsock_accept` and `vsock_connect`. It modifies the socket state machine and how socket errors (`sk_err`) are processed. There are no new data structures allocated, no changes to data copied to user space, and no modifications to buffer lengths or bounds checks. Any potential bugs introduced by these changes would be related to socket lifecycle management (e.g., use-after-free, memory leaks, or incorrect error codes), which are effectively detected by KASAN and standard kernel testing. There is no risk of uninitialized memory exposure or info-leaks, so a dedicated KMSAN fuzzing session is not required.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies the core vsock connection and accept logic, removing the 'rejected' state and altering how errors are handled during accept and connect operations. This is a functional change in reachable core kernel networking code.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit 4674c94137c356e9efd41d03c5d16de0a8fa89b1\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Mon Aug 10 21:12:18 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..3357ee62d10bf 100644\n--- a/include/net/af_vsock.h\n+++ b/include/net/af_vsock.h\n@@ -52,13 +52,10 @@ struct vsock_sock {\n \t * The listening socket is the head for both lists.  Sockets created\n \t * for connection requests are placed in the pending list until they\n \t * are connected, at which point they are put in the accept queue list\n-\t * so they can be accepted in accept().  If accept() cannot accept the\n-\t * connection, it is marked as rejected so the cleanup function knows\n-\t * to clean up the socket.\n+\t * so they can be accepted in accept().\n \t */\n \tstruct list_head pending_links;\n \tstruct list_head accept_queue;\n-\tbool rejected;\n \tstruct delayed_work connect_work;\n \tstruct delayed_work pending_work;\n \tstruct delayed_work close_work;\ndiff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c\nindex 622dbd0467994..1a287719f24a3 100644\n--- a/net/vmw_vsock/af_vsock.c\n+++ b/net/vmw_vsock/af_vsock.c\n@@ -38,10 +38,9 @@\n  * pending socket.  When that socket reaches the connected state, it is removed\n  * from the listener socket's pending list and enqueued in the listener\n  * socket's accept queue.  Callers of accept(2) will accept connected sockets\n- * from the listener socket's accept queue.  If the socket cannot be accepted\n- * for some reason then it is marked rejected.  Once the connection is\n- * accepted, it is owned by the user process and the responsibility for cleanup\n- * falls with that user process.\n+ * from the listener socket's accept queue. Once the connection is accepted,\n+ * it is owned by the user process and the responsibility for cleanup falls\n+ * with that user process.\n  *\n  * - It is possible that these pending sockets will never reach the connected\n  * state; in fact, we may never receive another packet after the connection\n@@ -49,9 +48,7 @@\n  * future, after some amount of time passes where a connection should have been\n  * established.  This function ensures that the socket is off all lists so it\n  * cannot be retrieved, then drops all references to the socket so it is cleaned\n- * up (sock_put() -\u003e sk_free() -\u003e our sk_destruct implementation).  Note this\n- * function will also cleanup rejected sockets, those that reach the connected\n- * state but leave it before they have been accepted.\n+ * up (sock_put() -\u003e sk_free() -\u003e our sk_destruct implementation).\n  *\n  * - Lock ordering for pending or accept queue sockets is:\n  *\n@@ -774,11 +771,10 @@ static void vsock_pending_work(struct work_struct *work)\n \n \tif (vsock_is_pending(sk)) {\n \t\tvsock_remove_pending(listener, sk);\n-\t} else if (!vsk-\u003erejected) {\n-\t\t/* We are not on the pending list and accept() did not reject\n-\t\t * us, so we must have been accepted by our user process.  We\n-\t\t * just need to drop our references to the sockets and be on\n-\t\t * our way.\n+\t} else {\n+\t\t/* We are not on the pending list so we must have been accepted\n+\t\t * by our user process. We just need to drop our references to\n+\t\t * the sockets and be on our way.\n \t\t */\n \t\tcleanup = false;\n \t\tgoto out;\n@@ -942,7 +938,6 @@ static struct sock *__vsock_create(struct net *net,\n \tvsk-\u003elistener = NULL;\n \tINIT_LIST_HEAD(\u0026vsk-\u003epending_links);\n \tINIT_LIST_HEAD(\u0026vsk-\u003eaccept_queue);\n-\tvsk-\u003erejected = false;\n \tvsk-\u003esent_request = false;\n \tvsk-\u003eignore_connecting_rst = false;\n \tWRITE_ONCE(vsk-\u003epeer_shutdown, 0);\n@@ -1847,12 +1842,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\n \t\tprepare_to_wait(sk_sleep(sk), \u0026wait, TASK_INTERRUPTIBLE);\n \t}\n \n-\tif (sk-\u003esk_err) {\n-\t\terr = -sk-\u003esk_err;\n+\terr = sock_error(sk);\n+\tif (err) {\n \t\tsk-\u003esk_state = TCP_CLOSE;\n \t\tsock-\u003estate = SS_UNCONNECTED;\n-\t} else {\n-\t\terr = 0;\n \t}\n \n out_wait:\n@@ -1893,7 +1886,7 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,\n \ttimeout = sock_rcvtimeo(listener, arg-\u003eflags \u0026 O_NONBLOCK);\n \n \twhile ((connected = vsock_dequeue_accept(listener)) == NULL \u0026\u0026\n-\t       listener-\u003esk_err == 0 \u0026\u0026 timeout != 0) {\n+\t\ttimeout != 0) {\n \t\tprepare_to_wait(sk_sleep(listener), \u0026wait, TASK_INTERRUPTIBLE);\n \t\trelease_sock(listener);\n \t\ttimeout = schedule_timeout(timeout);\n@@ -1906,41 +1899,26 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,\n \t\t}\n \t}\n \n-\tif (listener-\u003esk_err) {\n-\t\terr = -listener-\u003esk_err;\n-\t} else if (!connected) {\n-\t\terr = -EAGAIN;\n-\t}\n-\n \tif (connected) {\n \t\tsk_acceptq_removed(listener);\n \n \t\tlock_sock_nested(connected, SINGLE_DEPTH_NESTING);\n \t\tvconnected = vsock_sk(connected);\n \n-\t\t/* If the listener socket has received an error, then we should\n-\t\t * reject this socket and return.  Note that we simply mark the\n-\t\t * socket rejected, drop our reference, and let the cleanup\n-\t\t * function handle the cleanup; the fact that we found it in\n-\t\t * the listener's accept queue guarantees that the cleanup\n-\t\t * function hasn't run yet.\n-\t\t */\n-\t\tif (err) {\n-\t\t\tvconnected-\u003erejected = true;\n-\t\t} else {\n-\t\t\tnewsock-\u003estate = SS_CONNECTED;\n-\t\t\tsock_graft(connected, newsock);\n+\t\tnewsock-\u003estate = SS_CONNECTED;\n+\t\tsock_graft(connected, newsock);\n \n-\t\t\tset_bit(SOCK_CUSTOM_SOCKOPT,\n-\t\t\t\t\u0026connected-\u003esk_socket-\u003eflags);\n+\t\tset_bit(SOCK_CUSTOM_SOCKOPT,\n+\t\t\t\u0026connected-\u003esk_socket-\u003eflags);\n \n-\t\t\tif (vsock_msgzerocopy_allow(vconnected-\u003etransport))\n-\t\t\t\tset_bit(SOCK_SUPPORT_ZC,\n-\t\t\t\t\t\u0026connected-\u003esk_socket-\u003eflags);\n-\t\t}\n+\t\tif (vsock_msgzerocopy_allow(vconnected-\u003etransport))\n+\t\t\tset_bit(SOCK_SUPPORT_ZC,\n+\t\t\t\t\u0026connected-\u003esk_socket-\u003eflags);\n \n \t\trelease_sock(connected);\n \t\tsock_put(connected);\n+\t} else {\n+\t\terr = -EAGAIN;\n \t}\n \n out:\n"
}

best-expensive

null

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_accept",
    "vsock_pending_work"
  ],
  "Reasoning": "The patch modifies the core vsock connection and accept logic, removing the 'rejected' state and altering how errors are handled during accept and connect operations. This is a functional change in reachable core kernel networking code.",
  "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 4674c94137c356e9efd41d03c5d16de0a8fa89b1
Author: syz-cluster <triage@syzkaller.com>
Date:   Mon Aug 10 21:12:18 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 30046a3c20f73..3357ee62d10bf 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -52,13 +52,10 @@ struct vsock_sock {
 	 * The listening socket is the head for both lists.  Sockets created
 	 * for connection requests are placed in the pending list until they
 	 * are connected, at which point they are put in the accept queue list
-	 * so they can be accepted in accept().  If accept() cannot accept the
-	 * connection, it is marked as rejected so the cleanup function knows
-	 * to clean up the socket.
+	 * so they can be accepted in accept().
 	 */
 	struct list_head pending_links;
 	struct list_head accept_queue;
-	bool rejected;
 	struct delayed_work connect_work;
 	struct delayed_work pending_work;
 	struct delayed_work close_work;
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 622dbd0467994..1a287719f24a3 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -38,10 +38,9 @@
  * pending socket.  When that socket reaches the connected state, it is removed
  * from the listener socket's pending list and enqueued in the listener
  * socket's accept queue.  Callers of accept(2) will accept connected sockets
- * from the listener socket's accept queue.  If the socket cannot be accepted
- * for some reason then it is marked rejected.  Once the connection is
- * accepted, it is owned by the user process and the responsibility for cleanup
- * falls with that user process.
+ * from the listener socket's accept queue. Once the connection is accepted,
+ * it is owned by the user process and the responsibility for cleanup falls
+ * with that user process.
  *
  * - It is possible that these pending sockets will never reach the connected
  * state; in fact, we may never receive another packet after the connection
@@ -49,9 +48,7 @@
  * future, after some amount of time passes where a connection should have been
  * established.  This function ensures that the socket is off all lists so it
  * cannot be retrieved, then drops all references to the socket so it is cleaned
- * up (sock_put() -> sk_free() -> our sk_destruct implementation).  Note this
- * function will also cleanup rejected sockets, those that reach the connected
- * state but leave it before they have been accepted.
+ * up (sock_put() -> sk_free() -> our sk_destruct implementation).
  *
  * - Lock ordering for pending or accept queue sockets is:
  *
@@ -774,11 +771,10 @@ static void vsock_pending_work(struct work_struct *work)
 
 	if (vsock_is_pending(sk)) {
 		vsock_remove_pending(listener, sk);
-	} else if (!vsk->rejected) {
-		/* We are not on the pending list and accept() did not reject
-		 * us, so we must have been accepted by our user process.  We
-		 * just need to drop our references to the sockets and be on
-		 * our way.
+	} else {
+		/* We are not on the pending list so we must have been accepted
+		 * by our user process. We just need to drop our references to
+		 * the sockets and be on our way.
 		 */
 		cleanup = false;
 		goto out;
@@ -942,7 +938,6 @@ static struct sock *__vsock_create(struct net *net,
 	vsk->listener = NULL;
 	INIT_LIST_HEAD(&vsk->pending_links);
 	INIT_LIST_HEAD(&vsk->accept_queue);
-	vsk->rejected = false;
 	vsk->sent_request = false;
 	vsk->ignore_connecting_rst = false;
 	WRITE_ONCE(vsk->peer_shutdown, 0);
@@ -1847,12 +1842,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
 
-	if (sk->sk_err) {
-		err = -sk->sk_err;
+	err = sock_error(sk);
+	if (err) {
 		sk->sk_state = TCP_CLOSE;
 		sock->state = SS_UNCONNECTED;
-	} else {
-		err = 0;
 	}
 
 out_wait:
@@ -1893,7 +1886,7 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,
 	timeout = sock_rcvtimeo(listener, arg->flags & O_NONBLOCK);
 
 	while ((connected = vsock_dequeue_accept(listener)) == NULL &&
-	       listener->sk_err == 0 && timeout != 0) {
+		timeout != 0) {
 		prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
 		release_sock(listener);
 		timeout = schedule_timeout(timeout);
@@ -1906,41 +1899,26 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,
 		}
 	}
 
-	if (listener->sk_err) {
-		err = -listener->sk_err;
-	} else if (!connected) {
-		err = -EAGAIN;
-	}
-
 	if (connected) {
 		sk_acceptq_removed(listener);
 
 		lock_sock_nested(connected, SINGLE_DEPTH_NESTING);
 		vconnected = vsock_sk(connected);
 
-		/* If the listener socket has received an error, then we should
-		 * reject this socket and return.  Note that we simply mark the
-		 * socket rejected, drop our reference, and let the cleanup
-		 * function handle the cleanup; the fact that we found it in
-		 * the listener's accept queue guarantees that the cleanup
-		 * function hasn't run yet.
-		 */
-		if (err) {
-			vconnected->rejected = true;
-		} else {
-			newsock->state = SS_CONNECTED;
-			sock_graft(connected, newsock);
+		newsock->state = SS_CONNECTED;
+		sock_graft(connected, newsock);
 
-			set_bit(SOCK_CUSTOM_SOCKOPT,
-				&connected->sk_socket->flags);
+		set_bit(SOCK_CUSTOM_SOCKOPT,
+			&connected->sk_socket->flags);
 
-			if (vsock_msgzerocopy_allow(vconnected->transport))
-				set_bit(SOCK_SUPPORT_ZC,
-					&connected->sk_socket->flags);
-		}
+		if (vsock_msgzerocopy_allow(vconnected->transport))
+			set_bit(SOCK_SUPPORT_ZC,
+				&connected->sk_socket->flags);
 
 		release_sock(connected);
 		sock_put(connected);
+	} else {
+		err = -EAGAIN;
 	}
 
 out:

gemini-3.1-pro-preview

null

null

							input: 3704
							output: 34
							thoughts: 292
						

**Analyzing a VSock Patch**

Okay, so I'm looking at this patch that tweaks the vsock code, specifically `net/vmw_vsock/af_vsock.c` and `include/net/af_vsock.h`. My immediate thought is this looks like a functional change – it's touching core vsock logic. It's removing the `rejected` field from `struct vsock_sock`, which sounds pretty fundamental, and then it's changing the behavior of `vsock_pending_work`, `vsock_connect`, and `vsock_accept`. Specifically, in `vsock_accept`, the patch appears to be changing how errors on the listener socket are handled when dequeuing an accepted socket. Also, `vsock_connect` is now using `sock_error(sk)` instead of `sk->sk_err`, so that's a different approach to error checking during connection.

This definitely warrants a closer look because these are critical areas and functional modifications always require thorough scrutiny. This change definitely has potential functional impacts, and I'm thinking this is definitely worth fuzzing to make sure it's robust.

I need to nail down the exact implications. I'll need to focus on these functions: `vsock_pending_work`, `vsock_connect`, and `vsock_accept`. I'll also want to understand the impact of the configuration options, so I'm going to take a look at `net/vmw_vsock/Kconfig` to see if there are any settings that might influence this. I'll probably use `grepper` or `read-file` to get a handle on the Kconfig options.

{
  "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: 4587
							output: 32
							thoughts: 20
						

Okay, here's my take on those thoughts, tailored for an expert audience, and written as if they were my own immediate processing:

**VSOCKETS Configuration Check**

Alright, the configuration is set to `VSOCKETS`. That's a good starting point, but I need to make sure this is the *only* thing we're dealing with. No point in making assumptions. I need to quickly scan and verify that there aren't *any* other relevant configurations that might be in play or potentially override `VSOCKETS`, or interact with it in a way that I need to account for. No point going down a rabbit hole based on a single variable. So, the next step, as always, is a systems-level check. Let's make sure this is the only thing we need to consider in this section of the code/system. A quick look around the code base to find any other relevant configurations.

{
  "Expression": "depends on",
  "PathPrefix": "net/vmw_vsock/Kconfig"
}

{
  "Output": "net/vmw_vsock/Kconfig=19=config VSOCKETS_DIAG\nnet/vmw_vsock/Kconfig-20-\ttristate \"Virtual Sockets monitoring interface\"\nnet/vmw_vsock/Kconfig:21:\tdepends on VSOCKETS\nnet/vmw_vsock/Kconfig-22-\tdefault y\n--\nnet/vmw_vsock/Kconfig=29=config VSOCKETS_LOOPBACK\nnet/vmw_vsock/Kconfig-30-\ttristate \"Virtual Sockets loopback transport\"\nnet/vmw_vsock/Kconfig:31:\tdepends on VSOCKETS\nnet/vmw_vsock/Kconfig-32-\tdefault y\n--\nnet/vmw_vsock/Kconfig=41=config VMWARE_VMCI_VSOCKETS\nnet/vmw_vsock/Kconfig-42-\ttristate \"VMware VMCI transport for Virtual Sockets\"\nnet/vmw_vsock/Kconfig:43:\tdepends on VSOCKETS \u0026\u0026 VMWARE_VMCI\nnet/vmw_vsock/Kconfig-44-\thelp\n--\nnet/vmw_vsock/Kconfig=53=config VIRTIO_VSOCKETS\nnet/vmw_vsock/Kconfig-54-\ttristate \"virtio transport for Virtual Sockets\"\nnet/vmw_vsock/Kconfig:55:\tdepends on VSOCKETS \u0026\u0026 VIRTIO\nnet/vmw_vsock/Kconfig-56-\tselect VIRTIO_VSOCKETS_COMMON\n--\nnet/vmw_vsock/Kconfig=73=config HYPERV_VSOCKETS\nnet/vmw_vsock/Kconfig-74-\ttristate \"Hyper-V transport for Virtual Sockets\"\nnet/vmw_vsock/Kconfig:75:\tdepends on VSOCKETS \u0026\u0026 HYPERV_VMBUS\nnet/vmw_vsock/Kconfig-76-\thelp\n"
}

gemini-3.1-pro-preview

null

null

							input: 5327
							output: 38
							thoughts: 62
						

Here's my take on those considerations:

**VSOCK Configuration Deep Dive**

Okay, so I'm thinking about VSOCK configurations. Obviously, the core is the `VSOCKETS` option. That's the baseline, the foundation. I also know that `VSOCKETS_LOOPBACK` is really valuable for local testing and debugging. It's a lifesaver, being able to simulate a connection within the same host.

Now, I need to get my hands dirty. My next step will be to dive into the kernel code, specifically `net/vmw_vsock/af_vsock.c`. I'm going to carefully examine the implementations of `vsock_accept` and `vsock_connect` there. Understanding those two functions is absolutely critical to understanding how the connection lifecycle functions and the handshake is set up. They're going to tell me a lot about the core mechanics I'm dealing with.

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

{
  "Output": "net/vmw_vsock/af_vsock.c=1672=static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,\n--\nnet/vmw_vsock/af_vsock.c-1857-\nnet/vmw_vsock/af_vsock.c:1858:static int vsock_accept(struct socket *sock, struct socket *newsock,\nnet/vmw_vsock/af_vsock.c-1859-\t\t\tstruct proto_accept_arg *arg)\n--\nnet/vmw_vsock/af_vsock.c=2622=static const struct proto_ops vsock_stream_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2628-\t.socketpair = sock_no_socketpair,\nnet/vmw_vsock/af_vsock.c:2629:\t.accept = vsock_accept,\nnet/vmw_vsock/af_vsock.c-2630-\t.getname = vsock_getname,\n--\nnet/vmw_vsock/af_vsock.c=2644=static const struct proto_ops vsock_seqpacket_ops = {\n--\nnet/vmw_vsock/af_vsock.c-2650-\t.socketpair = sock_no_socketpair,\nnet/vmw_vsock/af_vsock.c:2651:\t.accept = vsock_accept,\nnet/vmw_vsock/af_vsock.c-2652-\t.getname = vsock_getname,\n"
}

gemini-3.1-pro-preview

null

null

							input: 6040
							output: 40
							thoughts: 130
						

**My Assessment of the Recent Kernel Patch**

Okay, so I've been reviewing this patch and here's the breakdown of my thinking. The core of this seems to revolve around changes to the `vsock` module, specifically in the `vsock_connect` and `vsock_accept` functions. It appears to remove the `rejected` field from `vsock_sock` and also simplifies the `vsock_pending_work` logic. The fact that these changes are within the reachable core kernel logic, specifically the vsock code, makes this interesting from a fuzzing perspective.

Given the scope and impact within the `vsock` module, I'm confident that this patch warrants further investigation. I'll flag it with `WorthFuzzing=true`.

For focused fuzzing efforts, the key symbols to keep an eye on are definitely `vsock_connect`, `vsock_accept`, and `vsock_pending_work`. I'll also want to ensure that the necessary kernel configurations are enabled, specifically `VSOCKETS` and `VSOCKETS_LOOPBACK`.

Now, before I commit to a full-blown fuzzing campaign, I want to quickly double check the nature of `vsock_pending_work`. I need to verify whether it's declared as static, and if it's inlined. This will affect how accessible it is and what kind of instrumentation I might need to apply for effective fuzzing.

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

{
  "Output": "net/vmw_vsock/af_vsock.c=747=static int vsock_send_shutdown(struct sock *sk, int mode)\n--\nnet/vmw_vsock/af_vsock.c-756-\nnet/vmw_vsock/af_vsock.c:757:static void vsock_pending_work(struct work_struct *work)\nnet/vmw_vsock/af_vsock.c-758-{\n--\nnet/vmw_vsock/af_vsock.c=904=static struct sock *__vsock_create(struct net *net,\n--\nnet/vmw_vsock/af_vsock.c-944-\tINIT_DELAYED_WORK(\u0026vsk-\u003econnect_work, vsock_connect_timeout);\nnet/vmw_vsock/af_vsock.c:945:\tINIT_DELAYED_WORK(\u0026vsk-\u003epending_work, vsock_pending_work);\nnet/vmw_vsock/af_vsock.c-946-\n"
}

gemini-3.1-pro-preview

null

null

							input: 6785
							output: 109
							thoughts: 36
						

Okay, here's my interpretation of those thoughts, summarized from my perspective as someone familiar with kernel internals:

**Analyzing vsock_pending_work and Code Flow**

Right, so `vsock_pending_work` is a workqueue callback. That immediately tells me a few things. First, it's not going to be inlined – workqueue callbacks are designed to be run asynchronously, off the critical path. Second, that also means we're likely grabbing its address somewhere. This is important to note for later, potentially for debugging or tracing. It gives me a crucial clue about how this code will be organized and called by the workqueue machinery.

My next step, looking at this context, is to call `set-results`. I need to figure out what that function is doing.

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_accept",
    "vsock_pending_work"
  ],
  "Reasoning": "The patch modifies the core vsock connection and accept logic, removing the 'rejected' state and altering how errors are handled during accept and connect operations. This is a functional change in reachable core kernel networking code.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "VSOCKETS",
    "VSOCKETS_LOOPBACK"
  ],
  "FocusSymbols": [
    "vsock_connect",
    "vsock_accept",
    "vsock_pending_work"
  ],
  "Reasoning": "The patch modifies the core vsock connection and accept logic, removing the 'rejected' state and altering how errors are handled during accept and connect operations. This is a functional change in reachable core kernel networking code.",
  "WorthFuzzing": true
}

{
  "WorthFuzzing": true
}

null

best-expensive

null

{
  "KMSANReasoning": "The patch removes the `rejected` field from `struct vsock_sock` and simplifies the error handling in `vsock_accept` and `vsock_connect`. It modifies the socket state machine and how socket errors (`sk_err`) are processed. There are no new data structures allocated, no changes to data copied to user space, and no modifications to buffer lengths or bounds checks. Any potential bugs introduced by these changes would be related to socket lifecycle management (e.g., use-after-free, memory leaks, or incorrect error codes), which are effectively detected by KASAN and standard kernel testing. There is no risk of uninitialized memory exposure or info-leaks, so a dedicated KMSAN fuzzing session is not required.",
  "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 4674c94137c356e9efd41d03c5d16de0a8fa89b1
Author: syz-cluster <triage@syzkaller.com>
Date:   Mon Aug 10 21:12:18 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 30046a3c20f73..3357ee62d10bf 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -52,13 +52,10 @@ struct vsock_sock {
 	 * The listening socket is the head for both lists.  Sockets created
 	 * for connection requests are placed in the pending list until they
 	 * are connected, at which point they are put in the accept queue list
-	 * so they can be accepted in accept().  If accept() cannot accept the
-	 * connection, it is marked as rejected so the cleanup function knows
-	 * to clean up the socket.
+	 * so they can be accepted in accept().
 	 */
 	struct list_head pending_links;
 	struct list_head accept_queue;
-	bool rejected;
 	struct delayed_work connect_work;
 	struct delayed_work pending_work;
 	struct delayed_work close_work;
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 622dbd0467994..1a287719f24a3 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -38,10 +38,9 @@
  * pending socket.  When that socket reaches the connected state, it is removed
  * from the listener socket's pending list and enqueued in the listener
  * socket's accept queue.  Callers of accept(2) will accept connected sockets
- * from the listener socket's accept queue.  If the socket cannot be accepted
- * for some reason then it is marked rejected.  Once the connection is
- * accepted, it is owned by the user process and the responsibility for cleanup
- * falls with that user process.
+ * from the listener socket's accept queue. Once the connection is accepted,
+ * it is owned by the user process and the responsibility for cleanup falls
+ * with that user process.
  *
  * - It is possible that these pending sockets will never reach the connected
  * state; in fact, we may never receive another packet after the connection
@@ -49,9 +48,7 @@
  * future, after some amount of time passes where a connection should have been
  * established.  This function ensures that the socket is off all lists so it
  * cannot be retrieved, then drops all references to the socket so it is cleaned
- * up (sock_put() -> sk_free() -> our sk_destruct implementation).  Note this
- * function will also cleanup rejected sockets, those that reach the connected
- * state but leave it before they have been accepted.
+ * up (sock_put() -> sk_free() -> our sk_destruct implementation).
  *
  * - Lock ordering for pending or accept queue sockets is:
  *
@@ -774,11 +771,10 @@ static void vsock_pending_work(struct work_struct *work)
 
 	if (vsock_is_pending(sk)) {
 		vsock_remove_pending(listener, sk);
-	} else if (!vsk->rejected) {
-		/* We are not on the pending list and accept() did not reject
-		 * us, so we must have been accepted by our user process.  We
-		 * just need to drop our references to the sockets and be on
-		 * our way.
+	} else {
+		/* We are not on the pending list so we must have been accepted
+		 * by our user process. We just need to drop our references to
+		 * the sockets and be on our way.
 		 */
 		cleanup = false;
 		goto out;
@@ -942,7 +938,6 @@ static struct sock *__vsock_create(struct net *net,
 	vsk->listener = NULL;
 	INIT_LIST_HEAD(&vsk->pending_links);
 	INIT_LIST_HEAD(&vsk->accept_queue);
-	vsk->rejected = false;
 	vsk->sent_request = false;
 	vsk->ignore_connecting_rst = false;
 	WRITE_ONCE(vsk->peer_shutdown, 0);
@@ -1847,12 +1842,10 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr,
 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
 
-	if (sk->sk_err) {
-		err = -sk->sk_err;
+	err = sock_error(sk);
+	if (err) {
 		sk->sk_state = TCP_CLOSE;
 		sock->state = SS_UNCONNECTED;
-	} else {
-		err = 0;
 	}
 
 out_wait:
@@ -1893,7 +1886,7 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,
 	timeout = sock_rcvtimeo(listener, arg->flags & O_NONBLOCK);
 
 	while ((connected = vsock_dequeue_accept(listener)) == NULL &&
-	       listener->sk_err == 0 && timeout != 0) {
+		timeout != 0) {
 		prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
 		release_sock(listener);
 		timeout = schedule_timeout(timeout);
@@ -1906,41 +1899,26 @@ static int vsock_accept(struct socket *sock, struct socket *newsock,
 		}
 	}
 
-	if (listener->sk_err) {
-		err = -listener->sk_err;
-	} else if (!connected) {
-		err = -EAGAIN;
-	}
-
 	if (connected) {
 		sk_acceptq_removed(listener);
 
 		lock_sock_nested(connected, SINGLE_DEPTH_NESTING);
 		vconnected = vsock_sk(connected);
 
-		/* If the listener socket has received an error, then we should
-		 * reject this socket and return.  Note that we simply mark the
-		 * socket rejected, drop our reference, and let the cleanup
-		 * function handle the cleanup; the fact that we found it in
-		 * the listener's accept queue guarantees that the cleanup
-		 * function hasn't run yet.
-		 */
-		if (err) {
-			vconnected->rejected = true;
-		} else {
-			newsock->state = SS_CONNECTED;
-			sock_graft(connected, newsock);
+		newsock->state = SS_CONNECTED;
+		sock_graft(connected, newsock);
 
-			set_bit(SOCK_CUSTOM_SOCKOPT,
-				&connected->sk_socket->flags);
+		set_bit(SOCK_CUSTOM_SOCKOPT,
+			&connected->sk_socket->flags);
 
-			if (vsock_msgzerocopy_allow(vconnected->transport))
-				set_bit(SOCK_SUPPORT_ZC,
-					&connected->sk_socket->flags);
-		}
+		if (vsock_msgzerocopy_allow(vconnected->transport))
+			set_bit(SOCK_SUPPORT_ZC,
+				&connected->sk_socket->flags);
 
 		release_sock(connected);
 		sock_put(connected);
+	} else {
+		err = -EAGAIN;
 	}
 
 out:

gemini-3.1-pro-preview

null

null

							input: 3701
							output: 179
							thoughts: 1155
						

**Analysis of the vsock Patch for Uninitialized Memory Risks**

Okay, let's break this down. We have a patch touching `af_vsock.c` and `af_vsock.h`. My immediate focus is on potential uninitialized memory exposures, so I'm looking for where new memory might be allocated or data could be mishandled.

First, the `rejected` field is being *removed* from `struct vsock_sock`. That alone doesn't scream "uninitialized memory," but it does force me to look at how that field was used. If it was guarding against accessing memory, I need to make sure the replacement logic is sound.

The patch changes `vsock_pending_work`, `vsock_connect`, and `vsock_accept`. Let's step through `vsock_accept`. The code used to check `listener->sk_err` in the `while` loop, and now it doesn't. My immediate thought is, did this introduce a race condition or a potential for returning an "invalid" socket? The old logic was more conservative. I need to be sure the new path still handles errors gracefully.

The old logic *also* had a `listener->sk_err` check *after* the loop, and if it was set *and* a `connected` socket had been dequeued, it would mark the `connected` socket as rejected.  Now the patch removes that check and processes an error in `vsock_accept`. Previously if there was an error on the listener socket, it would reject the accept socket. It looks like it still wakes up the sleep queue, and just loops again if nothing is dequeued. This looks like a change to how errors are handled, but doesn't *directly* introduce uninitialized memory.

`vsock_connect` now uses `sock_error(sk)` instead of directly checking `sk->sk_err`.  This is a good, standard practice.  `sock_error` gets and clears the error code. This is exactly what I'd expect to see in error handling. That's a refactoring, not a risk.

So, is there an *actual* risk of uninitialized memory? The critical thing is that there are no new memory allocations, no new data structures sent to user space, no new lengths. It's all about state machine logic and error handling. I'm not seeing any new places where uninitialized variables could be introduced.

Okay, let's double-check. The removal of `vconnected->rejected` is a critical change. And that's no longer checked by `vsock_pending_work`. If there was any access to this variable, it can cause use-after-free or leak, but KASAN will detect this. KMSAN is for *uninitialized* memory, which I don't see here.

This patch looks like a refactoring. It removes a field, simplifies error handling and the variables being used are `err`, `connected`, and `timeout`, which are initialized. I don't see anything here that could directly lead to uninitialized memory being exposed. No new pointers. No new allocations.

Therefore, this patch doesn't need KMSAN testing. I'll mark `NeedsKMSAN=false`. It's a logic change which can be covered by standard testing, and KASAN should pick up any lifecycle management issues.

{
  "KMSANReasoning": "The patch removes the `rejected` field from `struct vsock_sock` and simplifies the error handling in `vsock_accept` and `vsock_connect`. It modifies the socket state machine and how socket errors (`sk_err`) are processed. There are no new data structures allocated, no changes to data copied to user space, and no modifications to buffer lengths or bounds checks. Any potential bugs introduced by these changes would be related to socket lifecycle management (e.g., use-after-free, memory leaks, or incorrect error codes), which are effectively detected by KASAN and standard kernel testing. There is no risk of uninitialized memory exposure or info-leaks, so a dedicated KMSAN fuzzing session is not required.",
  "NeedsKMSAN": false
}

{
  "KMSANReasoning": "The patch removes the `rejected` field from `struct vsock_sock` and simplifies the error handling in `vsock_accept` and `vsock_connect`. It modifies the socket state machine and how socket errors (`sk_err`) are processed. There are no new data structures allocated, no changes to data copied to user space, and no modifications to buffer lengths or bounds checks. Any potential bugs introduced by these changes would be related to socket lifecycle management (e.g., use-after-free, memory leaks, or incorrect error codes), which are effectively detected by KASAN and standard kernel testing. There is no risk of uninitialized memory exposure or info-leaks, so a dedicated KMSAN fuzzing session is not required.",
  "NeedsKMSAN": false
}