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authorJohannes Berg <johannes@sipsolutions.net>2007-07-19 01:49:02 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:49 -0700
commitc71063c9c9dc232d0d51f936f237f7dc5681e8e3 (patch)
tree3f56b9e12c86b2afe9e613e868001654240aabb7 /kernel
parentd38e1d5aaee384698fcef9455d6e2df1d062a1d0 (diff)
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lockdep debugging: give stacktrace for init_error
When I started adding support for lockdep to 64-bit powerpc, I got a lockdep_init_error and with this patch was able to pinpoint why and where to put lockdep_init(). Let's support this generally for others adding lockdep support to their architecture. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/lockdep.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 156fce4960c..734da579ad1 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -375,6 +375,11 @@ unsigned int max_recursion_depth;
* about it later on, in lockdep_info().
*/
static int lockdep_init_error;
+static unsigned long lockdep_init_trace_data[20];
+static struct stack_trace lockdep_init_trace = {
+ .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
+ .entries = lockdep_init_trace_data,
+};
/*
* Various lockdep statistics:
@@ -662,6 +667,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
if (unlikely(!lockdep_initialized)) {
lockdep_init();
lockdep_init_error = 1;
+ save_stack_trace(&lockdep_init_trace);
}
#endif
@@ -3040,8 +3046,11 @@ void __init lockdep_info(void)
sizeof(struct held_lock) * MAX_LOCK_DEPTH);
#ifdef CONFIG_DEBUG_LOCKDEP
- if (lockdep_init_error)
- printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n");
+ if (lockdep_init_error) {
+ printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+ printk("Call stack leading to lockdep invocation was:\n");
+ print_stack_trace(&lockdep_init_trace, 0);
+ }
#endif
}