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-rw-r--r--kernel/locking/lockdep.c86
1 files changed, 72 insertions, 14 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 78c1c0ee6dc1..589d763a49b3 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -45,6 +45,8 @@
#include <linux/bitops.h>
#include <linux/gfp.h>
#include <linux/kmemcheck.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
#include <asm/sections.h>
@@ -308,10 +310,14 @@ static struct hlist_head chainhash_table[CHAINHASH_SIZE];
* It's a 64-bit hash, because it's important for the keys to be
* unique.
*/
-#define iterate_chain_key(key1, key2) \
- (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
- ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
- (key2))
+static inline u64 iterate_chain_key(u64 key, u32 idx)
+{
+ u32 k0 = key, k1 = key >> 32;
+
+ __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */
+
+ return k0 | (u64)k1 << 32;
+}
void lockdep_off(void)
{
@@ -708,7 +714,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
* yet. Otherwise we look it up. We cache the result in the lock object
* itself, so actual lookup of the hash should be once per lock object.
*/
-static inline struct lock_class *
+static struct lock_class *
register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
{
struct lockdep_subclass_key *key;
@@ -3585,7 +3591,35 @@ static int __lock_is_held(struct lockdep_map *lock)
return 0;
}
-static void __lock_pin_lock(struct lockdep_map *lock)
+static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
+{
+ struct pin_cookie cookie = NIL_COOKIE;
+ struct task_struct *curr = current;
+ int i;
+
+ if (unlikely(!debug_locks))
+ return cookie;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ struct held_lock *hlock = curr->held_locks + i;
+
+ if (match_held_lock(hlock, lock)) {
+ /*
+ * Grab 16bits of randomness; this is sufficient to not
+ * be guessable and still allows some pin nesting in
+ * our u32 pin_count.
+ */
+ cookie.val = 1 + (prandom_u32() >> 16);
+ hlock->pin_count += cookie.val;
+ return cookie;
+ }
+ }
+
+ WARN(1, "pinning an unheld lock\n");
+ return cookie;
+}
+
+static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3597,7 +3631,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
struct held_lock *hlock = curr->held_locks + i;
if (match_held_lock(hlock, lock)) {
- hlock->pin_count++;
+ hlock->pin_count += cookie.val;
return;
}
}
@@ -3605,7 +3639,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
WARN(1, "pinning an unheld lock\n");
}
-static void __lock_unpin_lock(struct lockdep_map *lock)
+static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3620,7 +3654,11 @@ static void __lock_unpin_lock(struct lockdep_map *lock)
if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
return;
- hlock->pin_count--;
+ hlock->pin_count -= cookie.val;
+
+ if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
+ hlock->pin_count = 0;
+
return;
}
}
@@ -3751,24 +3789,44 @@ int lock_is_held(struct lockdep_map *lock)
}
EXPORT_SYMBOL_GPL(lock_is_held);
-void lock_pin_lock(struct lockdep_map *lock)
+struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
{
+ struct pin_cookie cookie = NIL_COOKIE;
unsigned long flags;
if (unlikely(current->lockdep_recursion))
- return;
+ return cookie;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
- __lock_pin_lock(lock);
+ cookie = __lock_pin_lock(lock);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
+
+ return cookie;
}
EXPORT_SYMBOL_GPL(lock_pin_lock);
-void lock_unpin_lock(struct lockdep_map *lock)
+void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ __lock_repin_lock(lock, cookie);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_repin_lock);
+
+void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
unsigned long flags;
@@ -3779,7 +3837,7 @@ void lock_unpin_lock(struct lockdep_map *lock)
check_flags(flags);
current->lockdep_recursion = 1;
- __lock_unpin_lock(lock);
+ __lock_unpin_lock(lock, cookie);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}