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),
--
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