From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: john.stultz@linaro.org
Cc: linux-kernel@vger.kernel.org, tytso@mit.edu, rientjes@google.com,
dave@linux.vnet.ibm.com, 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, 18 May 2011 09:32:23 +0900 [thread overview]
Message-ID: <4DD31397.1090603@jp.fujitsu.com> (raw)
In-Reply-To: <1305580757-13175-3-git-send-email-john.stultz@linaro.org>
(2011/05/17 6:19), John Stultz wrote:
> Accessing 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 simplify correct
> locking in these cases, I've introduced a new %ptc format,
> which will print the corresponding task's comm.
>
> Example use:
> printk("%ptc: unaligned epc - sending SIGBUS.\n", current);
>
> CC: Ted Ts'o<tytso@mit.edu>
> CC: KOSAKI Motohiro<kosaki.motohiro@jp.fujitsu.com>
> CC: David Rientjes<rientjes@google.com>
> CC: Dave Hansen<dave@linux.vnet.ibm.com>
> CC: Andrew Morton<akpm@linux-foundation.org>
> CC: linux-mm@kvack.org
> Signed-off-by: John Stultz<john.stultz@linaro.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
WARNING: multiple messages have this Message-ID (diff)
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: john.stultz@linaro.org
Cc: linux-kernel@vger.kernel.org, tytso@mit.edu, rientjes@google.com,
dave@linux.vnet.ibm.com, 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, 18 May 2011 09:32:23 +0900 [thread overview]
Message-ID: <4DD31397.1090603@jp.fujitsu.com> (raw)
In-Reply-To: <1305580757-13175-3-git-send-email-john.stultz@linaro.org>
(2011/05/17 6:19), John Stultz wrote:
> Accessing 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 simplify correct
> locking in these cases, I've introduced a new %ptc format,
> which will print the corresponding task's comm.
>
> Example use:
> printk("%ptc: unaligned epc - sending SIGBUS.\n", current);
>
> CC: Ted Ts'o<tytso@mit.edu>
> CC: KOSAKI Motohiro<kosaki.motohiro@jp.fujitsu.com>
> CC: David Rientjes<rientjes@google.com>
> CC: Dave Hansen<dave@linux.vnet.ibm.com>
> CC: Andrew Morton<akpm@linux-foundation.org>
> CC: linux-mm@kvack.org
> Signed-off-by: John Stultz<john.stultz@linaro.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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next prev parent reply other threads:[~2011-05-18 0:32 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-16 21:19 [PATCH 0/3] v4 Improve task->comm locking situation John Stultz
2011-05-16 21:19 ` John Stultz
2011-05-16 21:19 ` [PATCH 1/3] comm: Introduce comm_lock seqlock to protect task->comm access John Stultz
2011-05-16 21:19 ` John Stultz
2011-05-16 22:01 ` Jiri Slaby
2011-05-16 22:01 ` Jiri Slaby
2011-05-17 1:47 ` John Stultz
2011-05-17 1:47 ` John Stultz
2011-05-18 0:28 ` KOSAKI Motohiro
2011-05-18 0:28 ` KOSAKI Motohiro
2011-05-16 21:19 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-16 21:19 ` John Stultz
2011-05-16 21:54 ` Jiri Slaby
2011-05-16 21:54 ` Jiri Slaby
2011-05-16 23:10 ` John Stultz
2011-05-16 23:10 ` John Stultz
2011-05-16 23:56 ` Joe Perches
2011-05-16 23:56 ` Joe Perches
2011-05-17 0:11 ` John Stultz
2011-05-17 0:11 ` John Stultz
2011-05-17 7:21 ` Jiri Slaby
2011-05-17 7:21 ` Jiri Slaby
2011-05-18 0:32 ` KOSAKI Motohiro [this message]
2011-05-18 0:32 ` KOSAKI Motohiro
2011-05-16 21:19 ` [PATCH 3/3] checkpatch.pl: Add check for task comm references John Stultz
2011-05-16 21:19 ` John Stultz
2011-05-16 21:29 ` Michal Nazarewicz
2011-05-16 21:29 ` Michal Nazarewicz
2011-05-16 21:34 ` David Rientjes
2011-05-16 21:34 ` David Rientjes
2011-05-16 23:04 ` Joe Perches
2011-05-16 23:04 ` Joe Perches
2011-05-16 23:11 ` Michal Nazarewicz
2011-05-16 23:11 ` Michal Nazarewicz
2011-05-16 23:22 ` Joe Perches
2011-05-16 23:22 ` Joe Perches
2011-05-18 3:16 ` [PATCH 0/3] v4 Improve task->comm locking situation Tetsuo Handa
2011-05-18 4:10 ` KOSAKI Motohiro
2011-05-18 4:15 ` John Stultz
2011-05-18 5:27 ` Tetsuo Handa
-- strict thread matches above, loose matches on Subject: below --
2011-05-17 20:47 [PATCH 0/3] v5 " 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 20:47 ` John Stultz
2011-05-17 21:42 ` Jiri Slaby
2011-05-17 21:42 ` Jiri Slaby
2011-05-17 21:52 ` Joe Perches
2011-05-17 21:52 ` Joe Perches
2011-05-17 22:04 ` Jiri Slaby
2011-05-17 22:04 ` Jiri Slaby
2011-05-17 22:17 ` Joe Perches
2011-05-17 22:17 ` Joe Perches
2011-05-17 22:17 ` John Stultz
2011-05-17 22:17 ` John Stultz
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
2011-05-12 23:02 ` John Stultz
2011-05-11 0:23 [RFC][PATCH 0/3] v2 Improve task->comm locking situation John Stultz
2011-05-11 0:23 ` [PATCH 2/3] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-11 0:23 ` John Stultz
2011-05-11 0:51 ` Joe Perches
2011-05-11 0:51 ` Joe Perches
2011-05-11 1:10 ` John Stultz
2011-05-11 1:10 ` John Stultz
2011-05-11 1:16 ` john stultz
2011-05-11 1:16 ` john stultz
2011-05-11 1:20 ` Joe Perches
2011-05-11 1:20 ` Joe Perches
2011-05-12 22:12 ` David Rientjes
2011-05-12 22:12 ` David Rientjes
2011-05-12 22:29 ` Joe Perches
2011-05-12 22:29 ` Joe Perches
2011-05-13 21:56 ` David Rientjes
2011-05-13 21:56 ` David Rientjes
2011-05-12 22:10 ` David Rientjes
2011-05-12 22:10 ` David Rientjes
2011-05-11 9:33 ` Américo Wang
2011-05-11 9:33 ` Américo Wang
2011-05-11 21:02 ` John Stultz
2011-05-11 21:02 ` John Stultz
2011-05-12 10:43 ` Américo Wang
2011-05-12 10:43 ` Américo Wang
2011-05-12 10:45 ` Américo Wang
2011-05-12 10:45 ` Américo Wang
2011-05-12 18:01 ` John Stultz
2011-05-12 18:01 ` John Stultz
2011-05-11 17:36 ` Andi Kleen
2011-05-11 17:36 ` Andi Kleen
2011-05-11 21:04 ` John Stultz
2011-05-11 21:04 ` John Stultz
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