linux-kernel - [tip: locking/core] locking/local_lock: Add missing owner initialization

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Message-ID: <162923127819.25758.13622427291765387358.tip-bot2@tip-bot2>
Date:   Tue, 17 Aug 2021 20:14:38 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: locking/core] locking/local_lock: Add missing owner initialization

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     d8bbd97ad0b99a9394f2cd8410b884c48e218cf0
Gitweb:        https://git.kernel.org/tip/d8bbd97ad0b99a9394f2cd8410b884c48e218cf0
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Sun, 15 Aug 2021 23:27:37 +02:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 17 Aug 2021 16:38:40 +02:00

locking/local_lock: Add missing owner initialization

If CONFIG_DEBUG_LOCK_ALLOC=y is enabled then local_lock_t has an 'owner'
member which is checked for consistency, but nothing initialized it to
zero explicitly.

The static initializer does so implicit, and the run time allocated per CPU
storage is usually zero initialized as well, but relying on that is not
really good practice.

Fixes: 91710728d172 ("locking: Introduce local_lock()")
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20210815211301.969975279@linutronix.de
---
 include/linux/local_lock_internal.h | 42 +++++++++++++++-------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index ded90b0..3f02b81 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -14,29 +14,14 @@ typedef struct {
 } local_lock_t;
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define LL_DEP_MAP_INIT(lockname)			\
+# define LOCAL_LOCK_DEBUG_INIT(lockname)		\
 	.dep_map = {					\
 		.name = #lockname,			\
 		.wait_type_inner = LD_WAIT_CONFIG,	\
-		.lock_type = LD_LOCK_PERCPU,			\
-	}
-#else
-# define LL_DEP_MAP_INIT(lockname)
-#endif
-
-#define INIT_LOCAL_LOCK(lockname)	{ LL_DEP_MAP_INIT(lockname) }
-
-#define __local_lock_init(lock)					\
-do {								\
-	static struct lock_class_key __key;			\
-								\
-	debug_check_no_locks_freed((void *)lock, sizeof(*lock));\
-	lockdep_init_map_type(&(lock)->dep_map, #lock, &__key, 0, \
-			      LD_WAIT_CONFIG, LD_WAIT_INV,	\
-			      LD_LOCK_PERCPU);			\
-} while (0)
+		.lock_type = LD_LOCK_PERCPU,		\
+	},						\
+	.owner = NULL,
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
 static inline void local_lock_acquire(local_lock_t *l)
 {
 	lock_map_acquire(&l->dep_map);
@@ -51,11 +36,30 @@ static inline void local_lock_release(local_lock_t *l)
 	lock_map_release(&l->dep_map);
 }
 
+static inline void local_lock_debug_init(local_lock_t *l)
+{
+	l->owner = NULL;
+}
 #else /* CONFIG_DEBUG_LOCK_ALLOC */
+# define LOCAL_LOCK_DEBUG_INIT(lockname)
 static inline void local_lock_acquire(local_lock_t *l) { }
 static inline void local_lock_release(local_lock_t *l) { }
+static inline void local_lock_debug_init(local_lock_t *l) { }
 #endif /* !CONFIG_DEBUG_LOCK_ALLOC */
 
+#define INIT_LOCAL_LOCK(lockname)	{ LOCAL_LOCK_DEBUG_INIT(lockname) }
+
+#define __local_lock_init(lock)					\
+do {								\
+	static struct lock_class_key __key;			\
+								\
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));\
+	lockdep_init_map_type(&(lock)->dep_map, #lock, &__key,  \
+			      0, LD_WAIT_CONFIG, LD_WAIT_INV,	\
+			      LD_LOCK_PERCPU);			\
+	local_lock_debug_init(lock);				\
+} while (0)
+
 #define __local_lock(lock)					\
 	do {							\
 		preempt_disable();				\