lockdep, kmemcheck: Annotate ->lock in lockdep_init_map()
Since commitf59de89
("lockdep: Clear whole lockdep_map on initialization"), lockdep_init_map() will clear all the struct. But it will break lock_set_class()/lock_set_subclass(). A typical race condition is like below: CPU A CPU B lock_set_subclass(lockA); lock_set_class(lockA); lockdep_init_map(lockA); /* lockA->name is cleared */ memset(lockA); __lock_acquire(lockA); /* lockA->class_cache[] is cleared */ register_lock_class(lockA); look_up_lock_class(lockA); WARN_ON_ONCE(class->name != lock->name); lock->name = name; So restore to what we have done before commitf59de89
but annotate ->lock with kmemcheck_mark_initialized() to suppress the kmemcheck warning reported in commitf59de89
. Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Borislav Petkov <bp@alien8.de> Suggested-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20111109080451.GB8124@zhy Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -44,6 +44,7 @@
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#include <linux/stringify.h>
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#include <linux/stringify.h>
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#include <linux/bitops.h>
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#include <linux/bitops.h>
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#include <linux/gfp.h>
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#include <linux/gfp.h>
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#include <linux/kmemcheck.h>
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#include <asm/sections.h>
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#include <asm/sections.h>
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@ -2950,7 +2951,12 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
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void lockdep_init_map(struct lockdep_map *lock, const char *name,
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void lockdep_init_map(struct lockdep_map *lock, const char *name,
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struct lock_class_key *key, int subclass)
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struct lock_class_key *key, int subclass)
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{
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{
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memset(lock, 0, sizeof(*lock));
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int i;
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kmemcheck_mark_initialized(lock, sizeof(*lock));
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for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
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lock->class_cache[i] = NULL;
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#ifdef CONFIG_LOCK_STAT
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#ifdef CONFIG_LOCK_STAT
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lock->cpu = raw_smp_processor_id();
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lock->cpu = raw_smp_processor_id();
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