Commit 9c35dd7f authored Mar 22, 2007 by Jarek Poplawski Committed by Linus Torvalds Mar 22, 2007

[PATCH] lockdep: debug_show_all_locks & debug_show_held_locks vs. debug_locks



lockdep's data shouldn't be used when debug_locks == 0 because it's not
updated after this, so it's more misleading than helpful.

PS: probably lockdep's current-> fields should be reset after it turns
debug_locks off: so, after printing a bug report, but before return from
exported functions, but there are really a lot of these possibilities (e.g.
 after DEBUG_LOCKS_WARN_ON), so, something could be missed.  (Of course
direct use of this fields isn't recommended either.)

Reported-by: Folkert van Heusden <folkert@vanheusden.com>
Inspired-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b4337692

kernel/lockdep.c

+8 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2742,6 +2742,10 @@ void debug_show_all_locks(void)
	int count = 10;		int count = 10;
	int unlock = 1;		int unlock = 1;

			if (unlikely(!debug_locks)) {
			printk("INFO: lockdep is turned off.\n");
			return;
			}
	printk("\nShowing all locks held in the system:\n");		printk("\nShowing all locks held in the system:\n");

	/*		/*
	@@ -2785,6 +2789,10 @@ EXPORT_SYMBOL_GPL(debug_show_all_locks);

	void debug_show_held_locks(struct task_struct *task)		void debug_show_held_locks(struct task_struct *task)
	{		{
			if (unlikely(!debug_locks)) {
			printk("INFO: lockdep is turned off.\n");
			return;
			}
	lockdep_print_held_locks(task);		lockdep_print_held_locks(task);
	}		}