linux-kernel - Re: [patch V4 02/10] rtmutex: Simplify rtmutex

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <53991FB4.2060001@cn.fujitsu.com>
Date:	Thu, 12 Jun 2014 11:34:12 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	LKML <linux-kernel@...r.kernel.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, Oleg Nesterov <oleg@...hat.com>
Subject: Re: [patch V4 02/10] rtmutex: Simplify rtmutex_slowtrylock()

On 06/12/2014 02:44 AM, Thomas Gleixner wrote:
> Oleg noticed that rtmutex_slowtrylock() has a pointless check for
> rt_mutex_owner(lock) != current.
> 
> To avoid calling try_to_take_rtmutex() we really want to check whether
> the lock has an owner at all or whether the trylock failed because the
> owner is NULL, but the RT_MUTEX_HAS_WAITERS bit is set. This covers
> the lock is owned by caller situation as well.
> 
> We can actually do this check lockless. trylock is taking a chance
> whether we take lock->wait_lock to do the check or not.
> 
> Add comments to the function while at it.
> 
> Reported-by: Oleg Nesterov <oleg@...hat.com>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---

Reviewed-by: Lai Jiangshan <laijs@...fujitsu.com>

Thanks,
Lai
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/