jump label: Add a WARN() if jump label key count goes negative

The count on a jump label key should never go negative. Add a WARN() to check for this condition. Signed-off-by: Jason Baron <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/3c68556121be4d1920417a3fe367da1ec38246b4.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar <[email protected]>
kyagi · Feb 22, 2012 · fadf046 · fadf046
1 parent 09bda44
commit fadf046
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
@@ -76,8 +76,11 @@ EXPORT_SYMBOL_GPL(jump_label_inc);
 static void __jump_label_dec(struct jump_label_key *key,
 		unsigned long rate_limit, struct delayed_work *work)
 {
-	if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex))
+	if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
+		WARN(atomic_read(&key->enabled) < 0,
+		     "jump label: negative count!\n");
 		return;
+	}
 
 	if (rate_limit) {
 		atomic_inc(&key->enabled);