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>
This commit is contained in:
Johannes Berg 2007-07-19 01:49:02 -07:00 committed by Linus Torvalds
parent d38e1d5aae
commit c71063c9c9

View file

@ -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
}