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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Yong Zhang <yong.zhang0@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>,
	linux-kernel@vger.kernel.org, sergey.senozhatsky@gmail.com,
	bp@alien8.de, Ingo Molnar <mingo@elte.hu>,
	Tejun Heo <tj@kernel.org>, David Rientjes <rientjes@google.com>,
	casteyde.christian@free.fr
Subject: Re: [PATCH 1/4] lockdep: lock_set_subclass() fix
Date: Tue, 08 Nov 2011 08:56:55 +0100	[thread overview]
Message-ID: <1320739015.2244.0.camel@twins> (raw)
In-Reply-To: <20111108025847.GB11439@zhy>

On Tue, 2011-11-08 at 10:58 +0800, Yong Zhang wrote:
> >  struct lockdep_map {
> > +     const char                      *name;
> >       struct lock_class_key           *key;
> >       struct lock_class               *class_cache[NR_LOCKDEP_CACHING_CLASSES];
> > -     const char                      *name;
> >  #ifdef CONFIG_LOCK_STAT
> >       int                             cpu;
> >       unsigned long                   ip;
> > diff --git a/kernel/lockdep.c b/kernel/lockdep.c
> > index e69434b..81855cf 100644
> > --- a/kernel/lockdep.c
> > +++ b/kernel/lockdep.c
> > @@ -2948,7 +2948,8 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
> >  void lockdep_init_map(struct lockdep_map *lock, const char *name,
> >                     struct lock_class_key *key, int subclass)
> >  {
> > -     memset(lock, 0, sizeof(*lock));
> > +     kmemcheck_mark_initialized(lock, 2*sizeof(void *));
> > +     memset(&lock->class_cache[0], 0, sizeof(*lock)-2*sizeof(void *));
> 
> That means ->key have chance to be 0 at some time, right? 

How? We only memset from class_cache onwards, leaving name and key
untouched.

  parent reply	other threads:[~2011-11-08  7:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-04  9:26 [PATCH 0/4] patches to cure race in lock_set_class() Yong Zhang
2011-11-04  9:26 ` [PATCH 1/4] lockdep: lock_set_subclass() fix Yong Zhang
2011-11-07 12:34   ` Peter Zijlstra
2011-11-07 13:31     ` Yong Zhang
2011-11-07 14:03       ` Tejun Heo
2011-11-07 13:54     ` Borislav Petkov
2011-11-07 15:28     ` Vegard Nossum
2011-11-07 16:10       ` Peter Zijlstra
2011-11-07 16:21         ` Tejun Heo
2011-11-07 16:26           ` Peter Zijlstra
2011-11-08  2:58         ` Yong Zhang
2011-11-08  3:02           ` Yong Zhang
2011-11-08  7:56           ` Peter Zijlstra [this message]
2011-11-08  8:14             ` Yong Zhang
2011-11-08  8:46               ` Peter Zijlstra
2011-11-08  9:07                 ` Yong Zhang
2011-11-08  9:37                   ` Yong Zhang
2011-11-08  9:40                   ` Peter Zijlstra
2011-11-09  8:04                     ` [PATCH 1/2] lockdep: kmemcheck: annotate ->lock in lockdep_init_map() Yong Zhang
2011-11-09  8:07                       ` [PATCH 2/2] lockdep: always try to set ->class_cache in register_lock_class() lockdep_init_map() Yong Zhang
2011-11-18 23:39                         ` [tip:core/locking] lockdep: Always " tip-bot for Yong Zhang
2011-12-06  9:39                       ` [tip:core/locking] lockdep, kmemcheck: Annotate ->lock in lockdep_init_map() tip-bot for Yong Zhang
2011-12-06 19:56                         ` David Rientjes
2011-12-06 20:14                       ` [tip:perf/urgent] " tip-bot for Yong Zhang
2011-11-08  2:22       ` [PATCH 1/4] lockdep: lock_set_subclass() fix Yong Zhang
2011-11-04  9:26 ` [RFC PATCH 2/4] lockdep: Let register_lock_class() can be called with/without graph_lock Yong Zhang
2011-11-04  9:26 ` [RFC PATCH 3/4] lockdep: split lockdep_init_map() Yong Zhang
2011-11-04  9:26 ` [RFC PATCH 4/4] lockdep: fix race condition in __lock_set_class() Yong Zhang
2011-11-07 12:30   ` Peter Zijlstra
2011-11-07 13:26     ` Yong Zhang
2011-11-06 11:52 ` [PATCH 0/4] patches to cure race in lock_set_class() Borislav Petkov

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