lockdep: continue lock debugging despite some taints

Impact: broaden lockdep checks

Lockdep is disabled after any kernel taints. This might be convenient
to ignore bad locking issues which sources come from outside the kernel
tree. Nevertheless, it might be a frustrating experience for the
staging developers or those who experience a warning but are focused
on another things that require lockdep.

The v2 of this patch simply don't disable anymore lockdep in case
of TAINT_CRAP and TAINT_WARN events.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LTP <ltp-list@lists.sourceforge.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg KH <gregkh@suse.de>
LKML-Reference: <1239412638-6739-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/panic.c

@@ -217,8 +217,10 @@ void add_taint(unsigned flag)
 	 * Can't trust the integrity of the kernel anymore.
 	 * We don't call directly debug_locks_off() because the issue
 	 * is not necessarily serious enough to set oops_in_progress to 1
+	 * Also we want to keep up lockdep for staging development and
+	 * post-warning case.
 	 */
-	if (__debug_locks_off())
+	if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
 		printk(KERN_WARNING "Disabling lockdep due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);