From: Steven Rostedt <rostedt@goodmis.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Li Zefan <lizf@cn.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
stable@kernel.org
Subject: Re: [PATCH 5/5] tracing: Do not record user stack trace from NMI context
Date: Sun, 14 Mar 2010 12:58:40 -0400 [thread overview]
Message-ID: <1268585920.13400.14.camel@localhost> (raw)
In-Reply-To: <20100314102747.GB5140@nowhere>
On Sun, 2010-03-14 at 11:27 +0100, Frederic Weisbecker wrote:
>
> Wow, that's a race :)
>
> In perf this is dealt with a special copy_from_user_nmi()
> (see in arch/x86/kernel/cpu/perf_event.c)
>
> May be save_stack_trace_user() should use that instead
> of a __copy_from_user_inatomic() based thing, just to
> cover such NMI corner race case.
>
Yeah, we should move the __copy_from_user_nmi() out of the perf code and
into the normal uaccess code. Then we could do as you suggest, and have
the stack code do:
if (in_nmi())
__copy_from_user_nmi();
else
__copy_from_user_inatomic();
Or maybe it would be best to have the __copy_from_user_inatomic() handle
it.
-- Steve
next prev parent reply other threads:[~2010-03-14 16:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-13 2:56 [PATCH 0/5][GIT PULL][2.6.34] tracing: urgent fixes Steven Rostedt
2010-03-13 2:56 ` [PATCH 1/5] ring-buffer: Move disabled check into preempt disable section Steven Rostedt
2010-03-13 2:56 ` [PATCH 2/5] function-graph: Init curr_ret_stack with ret_stack Steven Rostedt
2010-03-14 10:10 ` Frederic Weisbecker
2010-03-13 2:56 ` [PATCH 3/5] tracing: Use same local variable when resetting the ring buffer Steven Rostedt
2010-03-13 2:56 ` [PATCH 4/5] tracing: Disable buffer switching when starting or stopping trace Steven Rostedt
2010-03-13 2:57 ` [PATCH 5/5] tracing: Do not record user stack trace from NMI context Steven Rostedt
2010-03-14 10:27 ` Frederic Weisbecker
2010-03-14 15:28 ` Steven Rostedt
2010-03-14 16:58 ` Steven Rostedt [this message]
2010-03-17 2:08 ` Frederic Weisbecker
2010-03-14 22:05 ` John Kacur
2010-03-14 22:29 ` Steven Rostedt
2010-03-13 7:25 ` [PATCH 0/5][GIT PULL][2.6.34] tracing: urgent fixes Ingo Molnar
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=1268585920.13400.14.camel@localhost \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=fweisbec@gmail.com \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lizf@cn.fujitsu.com \
--cc=mingo@elte.hu \
--cc=stable@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 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.