On 12/03/2017 01:24 PM, Eric Biggers wrote:

On Sun, Nov 19, 2017 at 02:36:01AM -0800, syzbot wrote:

quoted

Hello,

syzkaller hit the following crash on
d9e0e63d9a6f88440eb201e1491fcf730272c706
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

Unfortunately, I don't have any reproducer for this bug yet.


Use struct sctp_sack_info instead

============================================
WARNING: possible recursive locking detected
4.14.0-rc8-next-20171110+ #40 Not tainted
--------------------------------------------
syz-executor6/21462 is trying to acquire lock:
 (&q->blk_trace_mutex){+.+.}, at: [<ffffffff81760261>]
blk_trace_remove+0x21/0x40 kernel/trace/blktrace.c:373

but task is already holding lock:
 (&q->blk_trace_mutex){+.+.}, at: [<ffffffff81763b38>]
blk_trace_setup+0x38/0x70 kernel/trace/blktrace.c:606

other info that might help us debug this:
 Possible unsafe locking scenario:

#syz fix: blktrace: fix trace mutex deadlock

This is fixed in current -git.

-- 
Jens Axboe