From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>,
akpm@linuxfoundation.org, rostedt@goodmis.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Eric Dumazet <edumazet@google.com>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH 1/6] net: ip4_datagram_connect: Use correct form of statistics update
Date: Wed, 16 Oct 2013 10:35:45 +0200 [thread overview]
Message-ID: <20131016083545.GP10651@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20131015174745.197380080@linux.com>
On Tue, Oct 15, 2013 at 12:47:23PM -0500, Christoph Lameter wrote:
> ip4_datagram_connect is called with BH processing enabled. Therefore
> we cannot use IP_INC_STATS_BH but must use IP_INC_STATS which disables
> BH handling before incrementing the counter.
>
> The following trace is triggered without this patch:
>
> [ 9293.806634] __this_cpu_add operation in preemptible [00000000] code: ntpd/2150
You lost the BUG there; that really needs to be there:
- BUG makes people pay attention
- This was an actual BUG wasn't it?
Sure there can be false positives, but in all cases people should amend
the code. Sometimes with a comment explaining why the raw primitive
should be used; sometimes to fix an actual bug, but a patch needs to be
written. Therefore BUG!
next prev parent reply other threads:[~2013-10-16 8:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 17:47 [PATCH 0/6] percpu: Implement Preemption checks for __this_cpu operations V4b Christoph Lameter
2013-10-15 17:47 ` [PATCH 1/6] net: ip4_datagram_connect: Use correct form of statistics update Christoph Lameter
2013-10-15 18:36 ` Eric Dumazet
2013-10-16 6:09 ` Ingo Molnar
2013-10-16 8:35 ` Peter Zijlstra [this message]
2013-10-16 9:14 ` Eric Dumazet
2013-10-16 9:26 ` Ingo Molnar
2013-10-16 14:27 ` Christoph Lameter
2013-10-16 14:37 ` Eric Dumazet
2013-10-15 17:47 ` [PATCH 2/6] percpu: Add raw_cpu_ops Christoph Lameter
2013-10-15 17:47 ` [PATCH 3/6] mm: Use raw_cpu ops for determining current NUMA node Christoph Lameter
2013-10-16 8:38 ` Peter Zijlstra
2013-10-16 14:22 ` Christoph Lameter
2013-10-15 17:47 ` [PATCH 4/6] Use raw_cpu_write for initialization of per cpu refcount Christoph Lameter
2013-10-16 8:43 ` Peter Zijlstra
2013-10-15 17:47 ` [PATCH 5/6] net: __this_cpu_inc in route.c Christoph Lameter
2013-10-16 8:46 ` Peter Zijlstra
2013-10-16 9:22 ` Eric Dumazet
2013-10-16 10:25 ` Peter Zijlstra
2013-10-16 15:07 ` Christoph Lameter
2013-10-15 17:47 ` [PATCH 6/6] percpu: Add preemption checks to __this_cpu ops Christoph Lameter
2013-10-16 8:49 ` Peter Zijlstra
2013-10-16 15:09 ` Christoph Lameter
2013-10-16 15:36 ` Peter Zijlstra
2013-10-16 15:55 ` Christoph Lameter
2013-10-16 16:25 ` Peter Zijlstra
2013-10-16 16:52 ` Steven Rostedt
2013-10-16 17:11 ` Peter Zijlstra
2013-10-16 17:39 ` Steven Rostedt
2013-10-16 18:38 ` Peter Zijlstra
2013-10-17 19:22 ` Christoph Lameter
2013-10-17 21:13 ` Peter Zijlstra
[not found] <20131011175518.634285474@linux.com>
2013-10-11 17:54 ` [PATCH 1/6] net: ip4_datagram_connect: Use correct form of statistics update Christoph Lameter
2013-10-11 18:32 ` Eric Dumazet
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=20131016083545.GP10651@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=akpm@linuxfoundation.org \
--cc=cl@linux.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=tj@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