From: Linus Torvalds <torvalds@linux-foundation.org>
To: John Stultz <john.stultz@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Joe Perches <joe@perches.com>, Ingo Molnar <mingo@elte.hu>,
Michal Nazarewicz <mina86@mina86.com>,
Andy Whitcroft <apw@canonical.com>,
Jiri Slaby <jirislaby@gmail.com>,
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 0/4] v6 Improve task->comm locking situation
Date: Wed, 18 May 2011 12:58:17 -0700 [thread overview]
Message-ID: <BANLkTikV5EUfpXF1PG3wXLXhou2crm_u2Q@mail.gmail.com> (raw)
In-Reply-To: <1305682865-27111-1-git-send-email-john.stultz@linaro.org>
On Tue, May 17, 2011 at 6:41 PM, John Stultz <john.stultz@linaro.org> wrote:
>
> While this was brought up at the time, it was not considered
> problematic, as the comm writing was done in such a way that
> only null or incomplete comms could be read. However, recently
> folks have made it clear they want to see this issue resolved.
What folks?
I don't think a new lock (or any lock) is at all appropriate.
There's just no point. Just guarantee that the last byte is always
zero, and you're done.
If you just guarantee that, THERE IS NO RACE. The last byte never
changes. You may get odd half-way strings, but you've trivially
guaranteed that they are C NUL-terminated, with no locking, no memory
ordering, no nothing.
Anybody who asks for any locking is just being a silly git. Tell them
to man the f*ck up.
So I'm not going to apply anything like this for 2.6.39, but I'm also
not going to apply it for 40 or 41 or anything else.
I refuse to accept just stupid unnecessary crap.
Linus
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next prev parent reply other threads:[~2011-05-18 19:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-18 1:41 [PATCH 0/4] v6 Improve task->comm locking situation John Stultz
2011-05-18 1:41 ` [PATCH 1/4] comm: Introduce comm_lock spinlock to protect task->comm access John Stultz
2011-05-18 2:01 ` KOSAKI Motohiro
2011-05-18 4:11 ` John Stultz
2011-05-18 5:06 ` KOSAKI Motohiro
2011-05-18 1:41 ` [PATCH 2/4] comm: Add lock-free task->comm accessor John Stultz
2011-05-18 1:41 ` [PATCH 3/4] printk: Add %ptc to safely print a task's comm John Stultz
2011-05-18 1:41 ` [PATCH 4/4] checkpatch.pl: Add check for task comm references John Stultz
2011-05-18 6:25 ` [PATCH 0/4] v6 Improve task->comm locking situation Ingo Molnar
2011-05-18 7:05 ` Andrew Morton
2011-05-18 7:58 ` Ingo Molnar
2011-05-18 19:03 ` John Stultz
2011-05-18 19:33 ` Andrew Morton
2011-05-18 19:48 ` Ingo Molnar
2011-05-18 19:56 ` Andrew Morton
2011-05-18 20:48 ` Ingo Molnar
2011-05-18 19:58 ` Linus Torvalds [this message]
2011-05-20 10:41 ` KOSAKI Motohiro
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