From: "Ted Ts'o" <tytso@mit.edu>
To: Jens Axboe <axboe@kernel.dk>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: What am I doing wrong? submit_bio() suddenly stops working...
Date: Thu, 21 Oct 2010 23:34:24 -0400 [thread overview]
Message-ID: <20101022033424.GO3127@thunk.org> (raw)
In-Reply-To: <4CC07C67.9010502@kernel.dk>
On Thu, Oct 21, 2010 at 07:46:15PM +0200, Jens Axboe wrote:
> By the sound of things, if I were you I'd turn on the mem and slab
> debugging to catch use-before-init and use-after-free. Mysterious hangs
> in the IO sub system are usually caused by such bugs. And the regular
> debugging aids, just to see if that produces anything of interest.
It looks like it was a use-after-free bug in my code. I'm running a
full set of set of tests now, but so far, it's gotten a lot further
than it went before, so I think I've figured it out.
I'm not sure why it caused the weird behaviour that it did (I got as
far as figuring out that somehow we lost the unplug timer, so after
the queue got plugged it never got unplugged), but I'm not going to
ask too many questions. :-)
Maybe later on I'll try to figure out if there's any way to add some
kind of sanity checking so that screw ups in in the bio code's caller
cause a clearer failure (such as a BUG_ON), but that'll have to wait
for when I have some free time.
- Ted
next prev parent reply other threads:[~2010-10-22 3:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-21 2:00 What am I doing wrong? submit_bio() suddenly stops working Theodore Ts'o
2010-10-21 6:59 ` Jens Axboe
2010-10-21 16:55 ` Ted Ts'o
2010-10-21 17:41 ` Boaz Harrosh
2010-10-21 18:07 ` Jens Axboe
2010-10-22 13:04 ` Peter Zijlstra
2010-10-22 14:08 ` Jens Axboe
2010-10-21 18:14 ` Ted Ts'o
2010-10-21 18:21 ` Jens Axboe
2010-10-21 17:46 ` Jens Axboe
2010-10-21 21:29 ` Ted Ts'o
2010-10-22 3:34 ` Ted Ts'o [this message]
2010-10-22 7:19 ` Jens Axboe
2010-10-23 14:48 ` Ted Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101022033424.GO3127@thunk.org \
--to=tytso@mit.edu \
--cc=axboe@kernel.dk \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox