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Commit c71063c9 authored by Johannes Berg's avatar Johannes Berg Committed by Linus Torvalds
Browse files

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: default avatarJohannes 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d38e1d5a

kernel/lockdep.c

+11 −2
Original line number Diff line number Diff line
@@ -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

}