From: Ingo Molnar <mingo@elte.hu>
To: Pekka Paalanen <pq@iki.fi>
Cc: Vegard Nossum <vegard.nossum@gmail.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <srostedt@redhat.com>,
proski@gnu.org
Subject: Re: mmiotrace broken in linux-next (8-bit writes only)
Date: Tue, 1 Jul 2008 10:15:16 +0200 [thread overview]
Message-ID: <20080701081516.GA3473@elte.hu> (raw)
In-Reply-To: <20080630234837.118fff8c@daedalus.pq.iki.fi>
* Pekka Paalanen <pq@iki.fi> wrote:
> The moment mmiotrace is enabled, I hit a NULL deref in:
>
> IP: [<ffffffff80256e71>] __trace_special+0x17c/0x23a
> Call Trace:
> [<ffffffff802573cc>] ftrace_special+0x6f/0x9a
> [<ffffffff8023e3e4>] down+0x19/0x4a
> [<ffffffff80228adc>] acquire_console_sem+0x42/0x58
> [<ffffffff8035d273>] con_flush_chars+0x28/0x43
> [<ffffffff80354a70>] write_chan+0x22e/0x334
> [<ffffffff802244e9>] ? default_wake_function+0x0/0xf
> [<ffffffff8035236d>] tty_write+0x195/0x228
> [<ffffffff80354842>] ? write_chan+0x0/0x334
> [<ffffffff8027c23a>] vfs_write+0xae/0x137
> [<ffffffff8027c6e3>] sys_write+0x47/0x70
> [<ffffffff8020b1db>] system_call_after_swapgs+0x7b/0x80
>
> which means 'entry' in __trace_special() is NULL.
>
> - ftrace_special(sem->count, 0, __LINE__);
> spin_lock_irqsave(&sem->lock, flags);
applied to tip/tracing/ftrace - thanks Pekka. This was a leftover line
from semaphore debugging.
Ingo
prev parent reply other threads:[~2008-07-01 8:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080628214626.5f9199d7@daedalus.pq.iki.fi>
[not found] ` <20080630123736.GA4011@elte.hu>
2008-06-30 20:48 ` mmiotrace broken in linux-next (8-bit writes only) Pekka Paalanen
2008-06-30 21:41 ` Vegard Nossum
2008-07-22 19:00 ` [PATCH] x86: fix mmiotrace 8-bit register decoding Pekka Paalanen
2008-07-26 15:55 ` Ingo Molnar
2008-07-01 8:15 ` Ingo Molnar [this message]
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=20080701081516.GA3473@elte.hu \
--to=mingo@elte.hu \
--cc=linux-kernel@vger.kernel.org \
--cc=pq@iki.fi \
--cc=proski@gnu.org \
--cc=srostedt@redhat.com \
--cc=vegard.nossum@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.