On 2018年03月26日 08:01, syzbot wrote:
Hello,
syzbot hit the following crash on upstream commit
cb6416592bc2a8b731dabcec0d63cda270764fc6 (Sun Mar 25 17:45:10 2018 +0000)
Merge tag 'dmaengine-fix-4.16-rc7' of
git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/slave-dma
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=7f073540b1384a614e09
So far this crash happened 4 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6506789075943424
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=5716250550337536
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5142038655795200
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-5034017172441945317
compiler: gcc (GCC) 7.1.1 20170620
IMPORTANT: if you fix the bug, please add the following tag to the
commit:
Reported-by: syzbot+7f073540b1384a614...@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.
============================================
WARNING: possible recursive locking detected
4.16.0-rc6+ #366 Not tainted
--------------------------------------------
vhost-4248/4760 is trying to acquire lock:
(&vq->mutex){+.+.}, at: [<000000003482bddc>]
vhost_net_rx_peek_head_len drivers/vhost/net.c:633 [inline]
(&vq->mutex){+.+.}, at: [<000000003482bddc>] handle_rx+0xeb1/0x19c0
drivers/vhost/net.c:784
but task is already holding lock:
(&vq->mutex){+.+.}, at: [<000000004de72f44>] handle_rx+0x1f5/0x19c0
drivers/vhost/net.c:766
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&vq->mutex);
lock(&vq->mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
Yes, it's a missing of nesting notation.
Will post a patch soon.
Thanks
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