From: Andi Kleen <andi@firstfloor.org>
To: John Stultz <john.stultz@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ted Ts'o <tytso@mit.edu>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Dave Hansen <dave@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/3] printk: Add %ptc to safely print a task's comm
Date: Wed, 11 May 2011 10:36:54 -0700 [thread overview]
Message-ID: <m2sjsli1ft.fsf@firstfloor.org> (raw)
In-Reply-To: <1305073386-4810-3-git-send-email-john.stultz@linaro.org> (John Stultz's message of "Tue, 10 May 2011 17:23:05 -0700")
John Stultz <john.stultz@linaro.org> writes:
> Acessing task->comm requires proper locking. However in the past
> access to current->comm could be done without locking. This
> is no longer the case, so all comm access needs to be done
> while holding the comm_lock.
>
> In my attempt to clean up unprotected comm access, I've noticed
> most comm access is done for printk output. To simpify correct
> locking in these cases, I've introduced a new %ptc format,
> which will safely print the corresponding task's comm.
>
> Example use:
> printk("%ptc: unaligned epc - sending SIGBUS.\n", current);
Neat. But you probably want a checkpatch rule for this too
to catch new offenders.
-Andi
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next prev parent reply other threads:[~2011-05-11 17:37 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-11 0:23 [RFC][PATCH 0/3] v2 Improve task->comm locking situation John Stultz
2011-05-11 0:23 ` [PATCH 1/3] comm: Introduce comm_lock seqlock to protect task->comm access John Stultz
2011-05-11 17:39 ` Andi Kleen
2011-05-12 22:00 ` David Rientjes
2011-05-11 0:23 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-11 0:51 ` Joe Perches
2011-05-11 1:10 ` John Stultz
2011-05-11 1:16 ` john stultz
2011-05-11 1:20 ` Joe Perches
2011-05-12 22:12 ` David Rientjes
2011-05-12 22:29 ` Joe Perches
2011-05-13 21:56 ` David Rientjes
2011-05-12 22:10 ` David Rientjes
2011-05-11 9:33 ` Américo Wang
2011-05-11 21:02 ` John Stultz
2011-05-12 10:43 ` Américo Wang
2011-05-12 10:45 ` Américo Wang
2011-05-12 18:01 ` John Stultz
2011-05-11 17:36 ` Andi Kleen [this message]
2011-05-11 21:04 ` John Stultz
2011-05-11 0:23 ` [PATCH 3/3] comm: ext4: Protect task->comm access by using %ptc John Stultz
2011-05-12 22:14 ` David Rientjes
2011-05-12 22:29 ` John Stultz
2011-05-12 22:34 ` Andrew Morton
2011-05-12 23:02 [PATCH 0/3] v3 Improve task->comm locking situation John Stultz
2011-05-12 23:02 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-16 21:19 [PATCH 0/3] v4 Improve task->comm locking situation John Stultz
2011-05-16 21:19 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-16 21:54 ` Jiri Slaby
2011-05-16 23:10 ` John Stultz
2011-05-16 23:56 ` Joe Perches
2011-05-17 0:11 ` John Stultz
2011-05-17 7:21 ` Jiri Slaby
2011-05-18 0:32 ` KOSAKI Motohiro
2011-05-17 20:47 [PATCH 0/3] v5 Improve task->comm locking situation John Stultz
2011-05-17 20:47 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-17 21:42 ` Jiri Slaby
2011-05-17 21:52 ` Joe Perches
2011-05-17 22:04 ` Jiri Slaby
2011-05-17 22:17 ` Joe Perches
2011-05-17 22:17 ` John Stultz
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