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authorYong Zhang <yong.zhang0@gmail.com>2011-11-09 16:04:51 +0800
committerIngo Molnar <mingo@elte.hu>2011-12-06 18:18:13 +0100
commita33caeb118198286309859f014c0662f3ed54ed4 (patch)
treec9bc38bef15bd7167ab27e1285d56a1e6cef4549 /kernel/lockdep.c
parentddf6e0e50723b62ac76ed18eb53e9417c6eefba7 (diff)
lockdep, kmemcheck: Annotate ->lock in lockdep_init_map()
Since commit f59de89 ("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 commit f59de89 but annotate ->lock with kmemcheck_mark_initialized() to suppress the kmemcheck warning reported in commit f59de89. 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> Cc: <stable@kernel.org> 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>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index e69434b070d..b2e08c932d9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -44,6 +44,7 @@
#include <linux/stringify.h>
#include <linux/bitops.h>
#include <linux/gfp.h>
+#include <linux/kmemcheck.h>
#include <asm/sections.h>
@@ -2948,7 +2949,12 @@ 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));
+ int i;
+
+ kmemcheck_mark_initialized(lock, sizeof(*lock));
+
+ for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
+ lock->class_cache[i] = NULL;
#ifdef CONFIG_LOCK_STAT
lock->cpu = raw_smp_processor_id();