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From: Sasha Levin <sasha.levin@oracle.com>
To: Jamie Iles <jamie.iles@oracle.com>
Cc: mingo@kernel.org, peterz@infradead.org, penberg@kernel.org,
	acme@ghostprotocols.net, paulus@samba.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/11] liblockdep: support using LD_PRELOAD
Date: Fri, 08 Feb 2013 18:55:54 -0500	[thread overview]
Message-ID: <5115908A.2000302@oracle.com> (raw)
In-Reply-To: <20130208104318.GG3468@cedar>

On 02/08/2013 05:43 AM, Jamie Iles wrote:
> On Thu, Feb 07, 2013 at 09:31:22AM -0500, Sasha Levin wrote:
>> On 02/07/2013 05:28 AM, Jamie Iles wrote:
>>>> +int pthread_rwlock_init(pthread_rwlock_t *rwlock,
>>>>> +			const pthread_rwlockattr_t *attr)
>>>>> +{
>>>>> +	if (ll_pthread_rwlock_init == NULL)
>>>>> +		init_preload();
>>> Why is this one special, doesn't init_preload being a constructor make 
>>> this redundant?
>>
>> I was testing it on different things, and stumbled on an interesting case:
>> when pthread_mutex was taken from the constructor of a different module.
>>
>> In that case, the other constructor would try to init the mutex and take
>> a lock, but we would segfault because we haven't resolved the pthread
>> symbols yet ourselves (since our constructor was yet to be called).
> 
> Okay, that makes sense, but shouldn't we do this for all of the lock 
> operations?  pthread locks can be statically initialized and they are 
> initializaed lazily on the first access so I think that this could 
> happen on any of the lock operations.

hmm... I've had it only in init() because I thought it doesn't make sense
to actually lock/unlock in constructor code, but yeah - better safe than
sorry.


Thanks,
Sasha


  reply	other threads:[~2013-02-08 23:56 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-06 22:11 [PATCH 00/11] lockdep: LD_PRELOAD support Sasha Levin
2013-02-06 22:11 ` [PATCH 01/11] liblockdep: remove the need for liblockdep_init Sasha Levin
2013-02-06 22:11 ` [PATCH 02/11] liblockdep: remove the need for liblockdep_set_thread Sasha Levin
2013-02-06 22:11 ` [PATCH 03/11] perf: stop using liblockdep_init and liblockdep_set_thread Sasha Levin
2013-02-06 22:11 ` [PATCH 04/11] liblockdep: fix AA test Sasha Levin
2013-02-06 22:11 ` [PATCH 05/11] liblockdep: correct the ABCDBCDA test Sasha Levin
2013-02-06 22:11 ` [PATCH 06/11] liblockdep: rbtree support Sasha Levin
2013-02-06 22:11 ` [PATCH 07/11] liblockdep: prevent multiple declarations of CALLER_ADDR0 Sasha Levin
2013-02-06 22:11 ` [PATCH 08/11] liblockdep: keep headers declarations even if lib is disabled Sasha Levin
2013-02-06 22:11 ` [PATCH 09/11] liblockdep: support using LD_PRELOAD Sasha Levin
2013-02-07 10:28   ` Jamie Iles
2013-02-07 14:31     ` Sasha Levin
2013-02-08 10:43       ` Jamie Iles
2013-02-08 23:55         ` Sasha Levin [this message]
2013-02-06 22:11 ` [PATCH 10/11] liblockdep: add tests for the LD_PRELOAD feature Sasha Levin
2013-02-06 22:11 ` [PATCH 11/11] liblockdep: preload helper Sasha Levin
2013-02-07  6:19   ` Namhyung Kim
2013-02-07  6:55   ` Namhyung Kim
2013-02-07 14:29     ` Sasha Levin
2013-02-07  7:07 ` [PATCH 00/11] lockdep: LD_PRELOAD support Pekka Enberg

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