From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 5 Dec 2007 14:46:09 +0000 (+0100)
Subject: lockdep: fix debug_show_all_locks()
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~40338^2~2
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=856848737bd944c1db3ce0a66bbf67e56bd6f77d;p=mirror_ubuntu-focal-kernel.git

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 ed38bbfc48a3..7e2ca7c9d99c 100644
--- 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)