lockdep: fix internal double unlock during self-test
Lockdep, during self-test (when it was simulating double unlocks) was
sometimes unconditionally unlocking a spinlock when it had not been
locked. This won't work for ticket locks.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 723bd9f..4335f12 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2943,9 +2943,10 @@
struct list_head *head;
unsigned long flags;
int i;
+ int locked;
raw_local_irq_save(flags);
- graph_lock();
+ locked = graph_lock();
/*
* Unhash all classes that were created by this module:
@@ -2959,7 +2960,8 @@
zap_class(class);
}
- graph_unlock();
+ if (locked)
+ graph_unlock();
raw_local_irq_restore(flags);
}
@@ -2969,6 +2971,7 @@
struct list_head *head;
unsigned long flags;
int i, j;
+ int locked;
raw_local_irq_save(flags);
@@ -2987,7 +2990,7 @@
* Debug check: in the end all mapped classes should
* be gone.
*/
- graph_lock();
+ locked = graph_lock();
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
if (list_empty(head))
@@ -3000,7 +3003,8 @@
}
}
}
- graph_unlock();
+ if (locked)
+ graph_unlock();
out_restore:
raw_local_irq_restore(flags);