From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Jones <davej@codemonkey.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Chris Mason <clm@fb.com>, Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>, Jens Axboe <axboe@fb.com>,
Al Viro <viro@zeniv.linux.org.uk>, Josef Bacik <jbacik@fb.com>,
David Sterba <dsterba@suse.com>,
linux-btrfs <linux-btrfs@vger.kernel.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Dave Chinner <david@fromorbit.com>
Subject: Re: bio linked list corruption.
Date: Wed, 26 Oct 2016 15:51:01 -0700 [thread overview]
Message-ID: <CA+55aFyyP6VHOv6KbhVdMMtNfJLftbju_Ui2GNxXt0GgkKm0Jg@mail.gmail.com> (raw)
In-Reply-To: <20161026224025.mou27kki4bslftli@codemonkey.org.uk>
On Wed, Oct 26, 2016 at 3:40 PM, Dave Jones <davej@codemonkey.org.uk> wrote:
>
> I gave it a shot too for shits & giggles.
> This falls out during boot.
>
> [ 9.278420] WARNING: CPU: 0 PID: 1 at block/blk-mq.c:1181 blk_sq_make_request+0x465/0x4a0
Hmm. That's the
WARN_ON_ONCE(rq->mq_ctx != ctx);
that I added to blk_mq_merge_queue_io(), and I really think that
warning is valid, and the fact that it triggers shows that something
is wrong with locking.
We just did a
spin_lock(&ctx->lock);
and that lock is *supposed* to protect the __blk_mq_insert_request(),
but that uses rq->mq_ctx.
So if rq->mq_ctx != ctx, then we're locking the wrong context.
Jens - please explain to me why I'm wrong.
Or maybe I actually might have found the problem? In which case please
send me a patch that fixes it ;)
Dave: it might be a good idea to split that "WARN_ON_ONCE()" in
blk_mq_merge_queue_io() into two, since right now it can trigger both
for the
blk_mq_bio_to_request(rq, bio);
path _and_ for the
if (!blk_mq_attempt_merge(q, ctx, bio)) {
blk_mq_bio_to_request(rq, bio);
goto insert_rq;
path. If you split it into two: one before that "insert_rq:" label,
and one before the "goto insert_rq" thing, then we could see if it is
just one of the blk_mq_merge_queue_io() cases (or both) that is
broken..
Linus
next prev parent reply other threads:[~2016-10-26 22:51 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-11 14:45 btrfs bio linked list corruption Dave Jones
2016-10-11 15:11 ` Al Viro
2016-10-11 15:19 ` Dave Jones
2016-10-11 15:20 ` Chris Mason
2016-10-11 15:49 ` Dave Jones
2016-10-11 15:54 ` Chris Mason
2016-10-11 16:25 ` Dave Jones
2016-10-12 13:47 ` Dave Jones
2016-10-12 14:40 ` Dave Jones
2016-10-12 14:42 ` Chris Mason
2016-10-13 18:16 ` Dave Jones
2016-10-13 21:18 ` Chris Mason
2016-10-13 21:56 ` Dave Jones
2016-10-16 0:42 ` Dave Jones
2016-10-18 1:07 ` Chris Mason
2016-10-18 22:42 ` Dave Jones
2016-10-18 23:12 ` Jens Axboe
2016-10-18 23:31 ` Chris Mason
2016-10-18 23:36 ` Jens Axboe
2016-10-18 23:39 ` Linus Torvalds
2016-10-18 23:42 ` Chris Mason
2016-10-19 0:10 ` Linus Torvalds
2016-10-19 0:19 ` Chris Mason
2016-10-19 0:28 ` Linus Torvalds
2016-10-20 22:48 ` Dave Jones
2016-10-19 1:05 ` Andy Lutomirski
2016-10-20 22:50 ` Dave Jones
2016-10-20 23:01 ` Andy Lutomirski
2016-10-20 23:03 ` Dave Jones
2016-10-20 23:23 ` Andy Lutomirski
2016-10-21 20:02 ` Dave Jones
2016-10-21 20:17 ` Chris Mason
2016-10-21 20:23 ` Dave Jones
2016-10-21 20:38 ` Chris Mason
2016-10-21 20:41 ` Josef Bacik
2016-10-21 21:11 ` Dave Jones
2016-10-22 15:20 ` Dave Jones
2016-10-23 21:32 ` Chris Mason
2016-10-24 4:40 ` Dave Jones
2016-10-24 13:42 ` Chris Mason
2016-10-26 0:27 ` Dave Jones
2016-10-26 1:33 ` Linus Torvalds
2016-10-26 1:39 ` Linus Torvalds
2016-10-26 16:30 ` Dave Jones
2016-10-26 16:48 ` Linus Torvalds
2016-10-26 18:18 ` Dave Jones
2016-10-26 18:42 ` Dave Jones
2016-10-26 19:06 ` Linus Torvalds
2016-10-26 20:00 ` Chris Mason
2016-10-26 21:52 ` Chris Mason
2016-10-26 22:21 ` Linus Torvalds
2016-10-26 22:40 ` Dave Jones
2016-10-26 22:51 ` Linus Torvalds [this message]
2016-10-26 22:55 ` Jens Axboe
2016-10-26 22:58 ` Linus Torvalds
2016-10-26 23:03 ` Jens Axboe
2016-10-26 23:07 ` Dave Jones
2016-10-26 23:08 ` Linus Torvalds
2016-10-26 23:20 ` Jens Axboe
2016-10-26 23:38 ` Chris Mason
2016-10-26 23:47 ` Dave Jones
2016-10-27 0:00 ` Jens Axboe
2016-10-27 13:33 ` Chris Mason
2016-10-31 18:55 ` Dave Jones
2016-10-31 19:35 ` Linus Torvalds
2016-10-31 19:44 ` Chris Mason
2016-11-06 16:55 ` btrfs btree_ctree_super fault Dave Jones
2016-11-08 14:59 ` Dave Jones
2016-11-08 15:08 ` Chris Mason
2016-11-10 14:35 ` Dave Jones
2016-11-10 15:27 ` Chris Mason
2016-11-23 19:34 ` bio linked list corruption Dave Jones
2016-11-23 19:58 ` Dave Jones
2016-12-01 15:32 ` btrfs_destroy_inode warn (outstanding extents) Dave Jones
2016-12-03 16:48 ` Dave Jones
2016-12-07 16:15 ` Dave Jones
2016-12-09 21:12 ` Steven Rostedt
2016-12-04 23:04 ` bio linked list corruption Vegard Nossum
2016-12-05 11:10 ` Vegard Nossum
2016-12-05 17:09 ` Vegard Nossum
2016-12-05 17:21 ` Dave Jones
2016-12-05 17:55 ` Linus Torvalds
2016-12-05 19:11 ` Vegard Nossum
2016-12-05 20:10 ` Linus Torvalds
2016-12-05 20:35 ` Linus Torvalds
2016-12-05 21:33 ` Vegard Nossum
2016-12-06 8:42 ` Vegard Nossum
2016-12-06 8:16 ` Peter Zijlstra
2016-12-06 8:36 ` Ingo Molnar
2016-12-06 16:33 ` Linus Torvalds
2016-12-05 20:10 ` Vegard Nossum
2016-12-05 18:11 ` Andy Lutomirski
2016-12-05 18:25 ` Linus Torvalds
2016-12-05 18:26 ` Vegard Nossum
2016-10-26 23:19 ` Chris Mason
2016-10-26 23:21 ` Jens Axboe
2016-10-27 6:33 ` Christoph Hellwig
2016-10-27 16:34 ` Linus Torvalds
2016-10-27 16:36 ` Jens Axboe
2016-10-26 23:01 ` Dave Jones
2016-10-26 23:05 ` Jens Axboe
2016-10-26 22:52 ` Jens Axboe
2016-10-26 22:07 ` Linus Torvalds
2016-10-26 22:54 ` Chris Mason
2016-10-27 5:41 ` Dave Chinner
2016-10-27 17:23 ` Dave Jones
2016-10-24 20:06 ` Andy Lutomirski
2016-10-24 20:46 ` Linus Torvalds
2016-10-24 21:17 ` Linus Torvalds
2016-10-24 21:50 ` Linus Torvalds
2016-10-24 22:02 ` Chris Mason
2016-10-24 22:42 ` Andy Lutomirski
2016-10-25 0:00 ` Linus Torvalds
2016-10-25 1:09 ` Andy Lutomirski
2016-10-19 17:09 ` Philipp Hahn
2016-10-19 17:43 ` Linus Torvalds
2016-10-20 6:52 ` Ingo Molnar
2016-10-20 7:17 ` Thomas Gleixner
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