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Diffstat (limited to 'kernel/locking/lockdep.c')
-rw-r--r--kernel/locking/lockdep.c112
1 files changed, 99 insertions, 13 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2324ba5310db..81f1a7107c0e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -45,6 +45,7 @@
#include <linux/bitops.h>
#include <linux/gfp.h>
#include <linux/kmemcheck.h>
+#include <linux/random.h>
#include <asm/sections.h>
@@ -708,7 +709,7 @@ 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;
@@ -1999,6 +2000,7 @@ static inline int get_first_held_lock(struct task_struct *curr,
return ++i;
}
+#ifdef CONFIG_DEBUG_LOCKDEP
/*
* Returns the next chain_key iteration
*/
@@ -2069,6 +2071,7 @@ static void print_collision(struct task_struct *curr,
printk("\nstack backtrace:\n");
dump_stack();
}
+#endif
/*
* Checks whether the chain and the current held locks are consistent
@@ -2174,15 +2177,37 @@ cache_hit:
chain->irq_context = hlock->irq_context;
i = get_first_held_lock(curr, hlock);
chain->depth = curr->lockdep_depth + 1 - i;
+
+ BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
+ BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks));
+ BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes));
+
if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
chain->base = nr_chain_hlocks;
- nr_chain_hlocks += chain->depth;
for (j = 0; j < chain->depth - 1; j++, i++) {
int lock_id = curr->held_locks[i].class_idx - 1;
chain_hlocks[chain->base + j] = lock_id;
}
chain_hlocks[chain->base + j] = class - lock_classes;
}
+
+ if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS)
+ nr_chain_hlocks += chain->depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * Important for check_no_collision().
+ */
+ if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
+ if (debug_locks_off_graph_unlock())
+ return 0;
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
+ dump_stack();
+ return 0;
+ }
+#endif
+
hlist_add_head_rcu(&chain->entry, hash_head);
debug_atomic_inc(chain_lookup_misses);
inc_chains();
@@ -2930,6 +2955,11 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
return 1;
}
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+ return 2 * !!task->hardirq_context + !!task->softirq_context;
+}
+
static int separate_irq_context(struct task_struct *curr,
struct held_lock *hlock)
{
@@ -2938,8 +2968,6 @@ static int separate_irq_context(struct task_struct *curr,
/*
* Keep track of points where we cross into an interrupt context:
*/
- hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
- curr->softirq_context;
if (depth) {
struct held_lock *prev_hlock;
@@ -2971,6 +2999,11 @@ static inline int mark_irqflags(struct task_struct *curr,
return 1;
}
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+ return 0;
+}
+
static inline int separate_irq_context(struct task_struct *curr,
struct held_lock *hlock)
{
@@ -3239,6 +3272,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
hlock->acquire_ip = ip;
hlock->instance = lock;
hlock->nest_lock = nest_lock;
+ hlock->irq_context = task_irq_context(curr);
hlock->trylock = trylock;
hlock->read = read;
hlock->check = check;
@@ -3552,7 +3586,35 @@ 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;
@@ -3564,7 +3626,7 @@ 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;
}
}
@@ -3572,7 +3634,7 @@ 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;
@@ -3587,7 +3649,11 @@ 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;
}
}
@@ -3718,24 +3784,44 @@ 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;
@@ -3746,7 +3832,7 @@ 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);
}
generated by cgit v1.2.3 (git 2.39.0) at 2025-01-20 03:03:42 +0300