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From:   Jason Wang <jasowang@redhat.com>
Date:   Wed, 8 Jun 2022 09:19:06 +0800
Message-ID: <CACGkMEseR-vDzgei21jftC8Grm0Not+e1XEefyLgV8C4yfWOHQ@mail.gmail.com>
Subject: Re: [syzbot] INFO: task hung in add_early_randomness (2)
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     syzbot <syzbot+5b59d6d459306a556f54@syzkaller.appspotmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        linux-crypto@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux@dominikbrodowski.net, mpm@selenic.com,
        syzkaller-bugs@googlegroups.com,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>, yuehaibing@huawei.com
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On Tue, Jun 7, 2022 at 6:54 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Tue, Jun 07, 2022 at 05:05:41PM +0800, Jason Wang wrote:
> > On Tue, Jun 7, 2022 at 3:30 PM syzbot
> > <syzbot+5b59d6d459306a556f54@syzkaller.appspotmail.com> wrote:
> > >
> > > syzbot has bisected this issue to:
> > >
> > > commit 8b4ec69d7e098a7ddf832e1e7840de53ed474c77
> > > Author: Jason Wang <jasowang@redhat.com>
> > > Date:   Fri May 27 06:01:19 2022 +0000
> > >
> > >     virtio: harden vring IRQ
> > >
> > > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1175c3c7f00000
> > > start commit:   f2906aa86338 Linux 5.19-rc1
> > > git tree:       upstream
> > > final oops:     https://syzkaller.appspot.com/x/report.txt?x=1375c3c7f00000
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=1575c3c7f00000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=cbd131cc02ee620e
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=5b59d6d459306a556f54
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=104f4d4ff00000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14d6782df00000
> > >
> > > Reported-by: syzbot+5b59d6d459306a556f54@syzkaller.appspotmail.com
> > > Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ")
> > >
> > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > >
> >
> > I wonder if it's related to shared IRQ.
> >
> > Want to know if the attached patch works.
> >
> > Thanks
>
> Please, post patches inline.
> In this case I don't see the printk in the console.
>

Ok, let's try this:

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 13a7348cedff..1af55e576505 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2137,7 +2137,7 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
        if (unlikely(vq->broken)) {
                dev_warn_once(&vq->vq.vdev->dev,
                              "virtio vring IRQ raised before DRIVER_OK");
-               return IRQ_NONE;
+               return IRQ_HANDLED;
        }

        /* Just a hint for performance: so it's ok that this can be racy! */