linux-kernel - Re: [syzbot] [net] [virt] INFO: task hung in __vhost_worker

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Message-ID: <20250831073458.6191-1-hdanton@sina.com>
Date: Sun, 31 Aug 2025 15:34:57 +0800
From: Hillf Danton <hdanton@...a.com>
To: syzbot <syzbot+7f3bbe59e8dd2328a990@...kaller.appspotmail.com>
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net] [virt] INFO: task hung in __vhost_worker_flush

> Date: Sat, 30 Aug 2025 19:21:32 -0700	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    11e7861d680c Merge tag 'for-linus' of git://git.kernel.org..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17c5c242580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d4703ac89d9e185a
> dashboard link: https://syzkaller.appspot.com/bug?extid=7f3bbe59e8dd2328a990
> compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1671ba62580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1685aa62580000

#syz test

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -440,7 +440,9 @@ static bool vhost_run_work_list(void *da
 	struct vhost_worker *worker = data;
 	struct vhost_work *work, *work_next;
 	struct llist_node *node;
+	bool did = false;
 
+again:
 	node = llist_del_all(&worker->work_list);
 	if (node) {
 		__set_current_state(TASK_RUNNING);
@@ -455,9 +457,11 @@ static bool vhost_run_work_list(void *da
 			kcov_remote_stop();
 			cond_resched();
 		}
+		did = true;
+		goto again;
 	}
 
-	return !!node;
+	return did;
 }
 
 static void vhost_worker_killed(void *data)
--