From: John Stultz <john.stultz@linaro.org>
To: Jiri Slaby <jirislaby@gmail.com>
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 1/3] comm: Introduce comm_lock seqlock to protect task->comm access
Date: Mon, 16 May 2011 18:47:47 -0700 [thread overview]
Message-ID: <1305596867.2915.109.camel@work-vm> (raw)
In-Reply-To: <4DD19EB5.7060900@gmail.com>
On Tue, 2011-05-17 at 00:01 +0200, Jiri Slaby wrote:
> On 05/16/2011 11:19 PM, John Stultz wrote:
> > diff --git a/include/linux/init_task.h b/include/linux/init_task.h
> > index caa151f..b69d94b 100644
> > --- a/include/linux/init_task.h
> > +++ b/include/linux/init_task.h
> > @@ -161,6 +161,7 @@ extern struct cred init_cred;
> > .group_leader = &tsk, \
> > RCU_INIT_POINTER(.real_cred, &init_cred), \
> > RCU_INIT_POINTER(.cred, &init_cred), \
> > + .comm_lock = __SPIN_LOCK_UNLOCKED(tsk.comm_lock), \
>
> Hmm, you should also init the spinlock somewhere in copy_process.
> Otherwise when a process is forked in the middle of [gs]et_task_comm
> called on it on another cpu, you have two locked locks and only the
> parent's will be unlocked, right?
Ah, yep. Fixed for the next version.
thanks!
-john
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next prev parent reply other threads:[~2011-05-17 1:54 UTC|newest]
Thread overview: 27+ 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 ` [PATCH 1/3] comm: Introduce comm_lock seqlock to protect task->comm access John Stultz
2011-05-16 22:01 ` Jiri Slaby
2011-05-17 1:47 ` John Stultz [this message]
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 21:54 ` 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
2011-05-16 21:19 ` [PATCH 3/3] checkpatch.pl: Add check for task comm references John Stultz
2011-05-16 21:29 ` Michal Nazarewicz
2011-05-16 21:34 ` David Rientjes
2011-05-16 23:04 ` Joe Perches
2011-05-16 23:11 ` Michal Nazarewicz
2011-05-16 23:22 ` Joe Perches
-- strict thread matches above, loose matches on Subject: below --
2011-05-12 23:02 [PATCH 0/3] v3 Improve task->comm locking situation John Stultz
2011-05-12 23:02 ` [PATCH 1/3] comm: Introduce comm_lock seqlock to protect task->comm access John Stultz
2011-05-13 11:13 ` KOSAKI Motohiro
2011-05-13 18:27 ` John Stultz
2011-05-14 11:12 ` KOSAKI Motohiro
2011-05-16 20:34 ` 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 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
2011-04-28 4:03 [RFC][PATCH 0/3] Improve task->comm locking situation John Stultz
2011-04-28 4:03 ` [PATCH 1/3] comm: Introduce comm_lock seqlock to protect task->comm access John Stultz
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