On Sat, Jul 27, 2019 at 04:23:23PM +0800, Hillf Danton wrote: > > Fri, 26 Jul 2019 08:26:01 -0700 (PDT) > > syzbot has bisected this bug to: > > > > commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 > > Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > > Date: Sun Jul 7 22:41:56 2019 +0000 > > > > Linux 5.2 > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=118810bfa00000 > > start commit: 13bf6d6a Add linux-next specific files for 20190725 > > git tree: linux-next > > kernel config: https://syzkaller.appspot.com/x/.config?x=8ae987d803395886 > > dashboard link: https://syzkaller.appspot.com/bug?extid=36e93b425cd6eb54fcc1 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15112f3fa00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131ab578600000 > > > > Reported-by: syzbot+36e93b425cd6eb54fcc1@xxxxxxxxxxxxxxxxxxxxxxxxx > > Fixes: 0ecfebd2b524 ("Linux 5.2") > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -787,7 +787,6 @@ static void vhost_setup_uaddr(struct vho > size_t size, bool write) > { > struct vhost_uaddr *addr = &vq->uaddrs[index]; > - spin_lock(&vq->mmu_lock); > > addr->uaddr = uaddr; > addr->size = size; > @@ -797,7 +796,10 @@ static void vhost_setup_uaddr(struct vho > static void vhost_setup_vq_uaddr(struct vhost_virtqueue *vq) > { > spin_lock(&vq->mmu_lock); > - > + /* > + * deadlock if managing to take mmu_lock again while > + * setting up uaddr > + */ > vhost_setup_uaddr(vq, VHOST_ADDR_DESC, > (unsigned long)vq->desc, > vhost_get_desc_size(vq, vq->num), > -- Thanks! I reverted this whole commit. -- MST
