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authorPeter Zijlstra <peterz@infradead.org>2019-02-25 15:56:32 +0100
committerIngo Molnar <mingo@kernel.org>2019-02-28 07:55:50 +0100
commit72dcd505e8585857397207f28782c8ba55e553b5 (patch)
tree64445bcbee51543fbceb0d7614545b3ab7b67f15 /kernel/locking
parentf214737b75b0ee79763b5c058b9d5e83d711348d (diff)
locking/lockdep: Add module_param to enable consistency checks
And move the whole lot under CONFIG_DEBUG_LOCKDEP. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c46
1 files changed, 33 insertions, 13 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index c73bc4334bee..fda370ca529c 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -74,8 +74,6 @@ module_param(lock_stat, int, 0644);
#define lock_stat 0
#endif
-static bool check_data_structure_consistency;
-
/*
* lockdep_lock: protects the lockdep graph, the hashes and the
* class/list/hash allocators.
@@ -791,6 +789,8 @@ static bool assign_lock_key(struct lockdep_map *lock)
return true;
}
+#ifdef CONFIG_DEBUG_LOCKDEP
+
/* Check whether element @e occurs in list @h */
static bool in_list(struct list_head *e, struct list_head *h)
{
@@ -855,15 +855,15 @@ static bool check_lock_chain_key(struct lock_chain *chain)
* The 'unsigned long long' casts avoid that a compiler warning
* is reported when building tools/lib/lockdep.
*/
- if (chain->chain_key != chain_key)
+ if (chain->chain_key != chain_key) {
printk(KERN_INFO "chain %lld: key %#llx <> %#llx\n",
(unsigned long long)(chain - lock_chains),
(unsigned long long)chain->chain_key,
(unsigned long long)chain_key);
- return chain->chain_key == chain_key;
-#else
- return true;
+ return false;
+ }
#endif
+ return true;
}
static bool in_any_zapped_class_list(struct lock_class *class)
@@ -871,15 +871,15 @@ static bool in_any_zapped_class_list(struct lock_class *class)
struct pending_free *pf;
int i;
- for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf);
- i++, pf++)
+ for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf); i++, pf++) {
if (in_list(&class->lock_entry, &pf->zapped))
return true;
+ }
return false;
}
-static bool check_data_structures(void)
+static bool __check_data_structures(void)
{
struct lock_class *class;
struct lock_chain *chain;
@@ -896,7 +896,6 @@ static bool check_data_structures(void)
printk(KERN_INFO "class %px/%s is not in any class list\n",
class, class->name ? : "(?)");
return false;
- return false;
}
}
@@ -953,6 +952,27 @@ static bool check_data_structures(void)
return true;
}
+int check_consistency = 0;
+module_param(check_consistency, int, 0644);
+
+static void check_data_structures(void)
+{
+ static bool once = false;
+
+ if (check_consistency && !once) {
+ if (!__check_data_structures()) {
+ once = true;
+ WARN_ON(once);
+ }
+ }
+}
+
+#else /* CONFIG_DEBUG_LOCKDEP */
+
+static inline void check_data_structures(void) { }
+
+#endif /* CONFIG_DEBUG_LOCKDEP */
+
/*
* Initialize the lock_classes[] array elements, the free_lock_classes list
* and also the delayed_free structure.
@@ -4474,10 +4494,11 @@ static void remove_class_from_lock_chain(struct pending_free *pf,
if (chain_hlocks[i] != class - lock_classes)
continue;
/* The code below leaks one chain_hlock[] entry. */
- if (--chain->depth > 0)
+ if (--chain->depth > 0) {
memmove(&chain_hlocks[i], &chain_hlocks[i + 1],
(chain->base + chain->depth - i) *
sizeof(chain_hlocks[0]));
+ }
/*
* Each lock class occurs at most once in a lock chain so once
* we found a match we can break out of this loop.
@@ -4631,8 +4652,7 @@ static void __free_zapped_classes(struct pending_free *pf)
{
struct lock_class *class;
- if (check_data_structure_consistency)
- WARN_ON_ONCE(!check_data_structures());
+ check_data_structures();
list_for_each_entry(class, &pf->zapped, lock_entry)
reinit_class(class);