lockdep: fix debug_show_all_locks()

fix the oops that can be seen in:

   http://bugzilla.kernel.org/attachment.cgi?id=13828&action=view

it is not safe to print the locks of running tasks.

(even with this fix we have a small race - but this is a debug
 function after all.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index ed38bbf..7e2ca7c 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3173,6 +3173,13 @@ retry:
                printk(" locked it.\n");
 
        do_each_thread(g, p) {
+               /*
+                * It's not reliable to print a task's held locks
+                * if it's not sleeping (or if it's not the current
+                * task):
+                */
+               if (p->state == TASK_RUNNING && p != current)
+                       continue;
                if (p->lockdep_depth)
                        lockdep_print_held_locks(p);
                if (!unlock)