Re: BUG: soft lockup - CPU#1 stuck for 1024s!

From: John Stultz
Date: Tue Sep 11 2012 - 19:51:22 EST

On 09/11/2012 04:41 PM, Fengguang Wu wrote:
On Mon, Sep 10, 2012 at 10:06:33AM -0700, John Stultz wrote:
On 09/09/2012 12:59 AM, Fengguang Wu wrote:
Hi John,

The below lockup warning pops up very occasionally in kvm guest
kernels and it's bisected down to

commit 2a8c0883c3cfffcc148ea606e2a4e7453cd75e73
Author: John Stultz <john.stultz@xxxxxxxxxx>
Date: Fri Jul 13 01:21:56 2012 -0400

time: Move xtime_nsec adjustment underflow handling timekeeping_adjust

[ 8.340327] Freeing unused kernel memory: 460k freed
[ 1107.515496] [sched_delayed] sched: RT throttling activated
[ 1107.516439] BUG: soft lockup - CPU#1 stuck for 1024s! [swapper/1:0]

Thanks so much for sending this. One detail I'm curious about is
that these kernels from the Bug messages seem to be v3.6-rc1 or

Ingo had a fix 1d17d17484d40f2d5b35c79518597a2b25296996 ("time: Fix
adjustment cleanup bug in timekeeping_adjust") that landed in

Has this issue actually been seen on a 3.6-rc2+ kernel?
Nope. I tested -rc5 for 10000+ boots and it's obviously free from the bug.
Sorry for the noise!

No worries. Thanks so much for following up on this, and your continued testing!

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at