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* [PATCH RFC] debugobjects: Make stack check warning more informative
@ 2018-07-23 21:25 Joel Fernandes
  2018-07-23 21:54 ` Yang Shi
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Joel Fernandes @ 2018-07-23 21:25 UTC (permalink / raw)
  To: linux-kernel
  Cc: kernel-team, Joel Fernandes (Google),
	Thomas Gleixner, Yang Shi, Waiman Long, Arnd Bergmann, astrachan

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Recently we debugged an issue where debugobject tracking was telling
us of an annotation issue. Turns out the issue was due to the object in
concern being on a different stack which was due to another issue.

Discussing with tglx, he suggested printing the pointers and the
location of the stack for the currently running task. This helped find
the object was on the wrong stack. I turned the resulting patch into
something upstreamable, so that the error message is more informative
and can help in debugging for similar issues in the future.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 lib/debugobjects.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 994be4805cec..24c1df0d7466 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -360,9 +360,12 @@ static void debug_object_is_on_stack(void *addr, int onstack)
 
 	limit++;
 	if (is_on_stack)
-		pr_warn("object is on stack, but not annotated\n");
+		pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
+			 task_stack_page(current));
 	else
-		pr_warn("object is not on stack, but annotated\n");
+		pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
+			 task_stack_page(current));
+
 	WARN_ON(1);
 }
 
-- 
2.18.0.233.g985f88cf7e-goog


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2018-07-30 19:40 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-07-23 21:25 [PATCH RFC] debugobjects: Make stack check warning more informative Joel Fernandes
2018-07-23 21:54 ` Yang Shi
2018-07-24  0:33 ` Waiman Long
2018-07-30 19:39 ` [tip:core/debugobjects] " tip-bot for Joel Fernandes (Google)

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