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Date: Wed, 22 Apr 2026 09:36:51 +0900
From: Kohei Enju <kohei@enjuk.jp>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: syzbot <syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com>,
        jasowang@redhat.com, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [kvm?] [net?] [virt?] BUG: sleeping function called
 from invalid context in vhost_get_avail_idx
Message-ID: <aegXjsir7lWLc0pI@x1>
References: <69e6a414.050a0220.24bfd3.002d.GAE@google.com>
 <aeerTzpq8B-WTKeC@x1>
 <20260421165358-mutt-send-email-mst@kernel.org>
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In-Reply-To: <20260421165358-mutt-send-email-mst@kernel.org>

On 04/21 16:54, Michael S. Tsirkin wrote:
> > 
> > #syz test
> > 
> > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > index 80965181920c..c6536cad9c4f 100644
> > --- a/drivers/vhost/net.c
> > +++ b/drivers/vhost/net.c
> > @@ -560,7 +560,7 @@ static void vhost_net_busy_poll(struct vhost_net *net,
> >         busyloop_timeout = poll_rx ? rvq->busyloop_timeout:
> >                                      tvq->busyloop_timeout;
> > 
> > -       preempt_disable();
> > +       migrate_disable();
> >         endtime = busy_clock() + busyloop_timeout;
> > 
> >         while (vhost_can_busy_poll(endtime)) {
> > @@ -577,7 +577,7 @@ static void vhost_net_busy_poll(struct vhost_net *net,
> >                 cpu_relax();
> >         }
> > 
> > -       preempt_enable();
> > +       migrate_enable();
> > 
> >         if (poll_rx || sock_has_rx_data(sock))
> >                 vhost_net_busy_poll_try_queue(net, vq);
> 
> 
> 
> Makes sense but this stipped up the bot. Try again?

Hi Michael,

Thanks for taking a look.
I've retried the testing, and it looks good.
https://lore.kernel.org/all/69e8119f.a00a0220.17a17.001e.GAE@google.com/

Will send an official patch.