Re: [syzbot] [net?] [virt?] [kvm?] KASAN: slab-use-after-free Read in vhost_task_fn

[Hillf Danton]

On Tue, 30 Apr 2024 01:25:26 -0700
> syzbot found the following issue on:
> 
> HEAD commit:    bb7a2467e6be Add linux-next specific files for 20240426
> git tree:       linux-next
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16c30028980000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git  bb7a2467e6be

--- x/kernel/vhost_task.c
+++ y/kernel/vhost_task.c
@@ -100,6 +100,8 @@ void vhost_task_stop(struct vhost_task *
 	 * freeing it below.
 	 */
 	wait_for_completion(&vtsk->exited);
+	mutex_lock(&vtsk->exit_mutex);
+	mutex_unlock(&vtsk->exit_mutex);
 	kfree(vtsk);
 }
 EXPORT_SYMBOL_GPL(vhost_task_stop);
--