On 07/18/2007 05:41 AM, Dhaval Giani wrote:
> On Wed, Jul 18, 2007 at 01:07:00AM -0700, Andrew Morton wrote:
>> On Wed, 18 Jul 2007 13:26:48 +0530 Dhaval Giani <[EMAIL PROTECTED]> wrote:
>>
>>> I was running kernbench on top of 2.6.22-rc6-mm1 and I got a Hangcheck
>>> alert (This is when kernbench reached make -j).
>> hm, never had a report of that before. It's the first time I've seen
>> hangcheck produce anything useful, frankly.
>>
>> Was the softlockup detector not enabled?
>
> I notice CONFIG_DETECT_SOFTLOCKUP=y
>>> Also make -j is hanging.
>> Please try to capture the full sysrq-T output when it is hung.
>
> Available at http://dhaval.giani.googlepages.com/sysrq-t-trace.bz2
>
> In the meantime I will go and check if it was there in 2.6.22-rc4-mm2
>
Softlockup is broken in 2.6.22.
=======================================================================
Subject: fix the softlockup watchdog to actually work
From: Ingo Molnar <[EMAIL PROTECTED]>
this Xen related commit:
commit 966812dc98e6a7fcdf759cbfa0efab77500a8868
Author: Jeremy Fitzhardinge <[EMAIL PROTECTED]>
Date: Tue May 8 00:28:02 2007 -0700
Ignore stolen time in the softlockup watchdog
broke the softlockup watchdog to never report any lockups. (!)
print_timestamp defaults to 0, this makes the following condition
always true:
if (print_timestamp < (touch_timestamp + 1) ||
and we'll in essence never report soft lockups.
apparently the functionality of the soft lockup watchdog was never
actually tested with that patch applied ...
[this is -stable material too.]
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
kernel/softlockup.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
Index: linux/kernel/softlockup.c
===================================================================
--- linux.orig/kernel/softlockup.c
+++ linux/kernel/softlockup.c
@@ -79,10 +79,11 @@ void softlockup_tick(void)
print_timestamp = per_cpu(print_timestamp, this_cpu);
/* report at most once a second */
- if (print_timestamp < (touch_timestamp + 1) ||
- did_panic ||
- !per_cpu(watchdog_task, this_cpu))
+ if ((print_timestamp >= touch_timestamp &&
+ print_timestamp < (touch_timestamp + 1)) ||
+ did_panic || !per_cpu(watchdog_task, this_cpu)) {
return;
+ }
/* do not print during early bootup: */
if (unlikely(system_state != SYSTEM_RUNNING)) {
-
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