From: Peter Zijlstra <peterz@infradead.org>
To: Dave Jones <davej@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
jolsa@redhat.com
Subject: Re: trinity finds ftrace/perf bug. Film at 11.
Date: Thu, 3 Oct 2013 17:44:01 +0200 [thread overview]
Message-ID: <20131003154401.GO31370@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20130912183849.GA16674@redhat.com>
On Thu, Sep 12, 2013 at 02:38:49PM -0400, Dave Jones wrote:
> The current one I'm staring at is this from LIST_DEBUG..
>
> list_del corruption. next->prev should be prev (ffff88000fb812b0), but was ffff88000fb812b0. (next=ffff88009df8b7b0).
>
> The sharp eyed will notice that those first two addresses are actually the same.
> So we matched the next->prev != prev test, but at the time we got to the printk that follows
> in the WARN, the inverse was true. Smells like a race of some kind.
FWIW, I've not given up on this. I've found one bug in the list_entry
handling already -- although not this one.
Today I hit a more revealing error:
[ 8348.150303] list_del corruption. prev->next should be ffff88042839c108, but was 6b6b6b6b6b6b6b6b
And as we all know that 6b is POISON_FREE, so we're staring at a
use-after-free here.
Brain did give out for today though.. more staring at reference counts
tomorrow.
The sad thing is that reproduction takes forever on my machine; I need
to let trinity run for a good hour and then ^C abort the run. Only then
will I hit it fairly reliably.
next prev parent reply other threads:[~2013-10-03 15:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-11 13:54 Dave Jones
2013-09-12 18:19 ` Steven Rostedt
2013-09-12 18:38 ` Dave Jones
2013-10-03 15:44 ` Peter Zijlstra [this message]
2013-10-03 16:57 ` Ingo Molnar
2013-09-13 10:56 ` Peter Zijlstra
2013-09-13 14:16 ` Dave Jones
2013-09-16 9:37 ` Peter Zijlstra
2013-09-16 10:25 ` Ingo Molnar
2013-09-16 10:43 ` Peter Zijlstra
2013-09-16 16:45 ` Dave Jones
2013-09-16 16:44 ` Dave Jones
2013-09-18 11:34 ` Peter Zijlstra
2013-09-18 13:22 ` Dave Jones
2013-09-13 14:32 ` Steven Rostedt
2013-09-13 14:58 ` Peter Zijlstra
2013-09-13 11:14 ` Peter Zijlstra
2013-09-13 14:28 ` Dave Jones
2013-09-13 14:58 ` Peter Zijlstra
2013-11-19 19:18 ` [tip:perf/urgent] perf: Remove fragile swevent hlist optimization tip-bot for Peter Zijlstra
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=20131003154401.GO31370@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=davej@redhat.com \
--cc=fweisbec@gmail.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=rostedt@goodmis.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
Powered by JetHome