linux-kernel - [patch] softlockup: fix false positives on CONFIG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 28 Nov 2007 13:56:37 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>
Subject: [patch] softlockup: fix false positives on CONFIG_NOHZ


* Ingo Molnar <mingo@...e.hu> wrote:

> these can be fixed, but:
> 
> > This will introduce an up-to-one-second delay in responding to 
> > kthread_should_stop().  Is that bad?
> 
> grumble, it's bad. I guess David is right that this should be fixed 
> the right way ;-) So the above patch cannot go in.

Thomas found the right fix. David, could you try the fix below, does it 
fix those false positives on your nohz Niagara cores?

	Ingo

---------------->
Subject: softlockup: fix false positives on CONFIG_NOHZ
From: Thomas Gleixner <tglx@...utronix.de>

David Miller reported soft lockup false-positives that trigger
on NOHZ due to CPUs idling for more than 10 seconds.

The solution is touch the softlockup watchdog when we return from
idle. (by definition we are not 'locked up' when we were idle)

 http://bugzilla.kernel.org/show_bug.cgi?id=9409

Reported-by: David Miller <davem@...emloft.net>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 kernel/time/tick-sched.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux/kernel/time/tick-sched.c
===================================================================
--- linux.orig/kernel/time/tick-sched.c
+++ linux/kernel/time/tick-sched.c
@@ -133,6 +133,8 @@ void tick_nohz_update_jiffies(void)
 	if (!ts->tick_stopped)
 		return;
 
+	touch_softlockup_watchdog();
+
 	cpu_clear(cpu, nohz_cpu_mask);
 	now = ktime_get();
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/