From: Ben Hutchings <ben@decadent.org.uk>
To: John Stultz <johnstul@us.ibm.com>
Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>,
stable@vger.kernel.org,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 00/11] 3.2-stable: Fix for leapsecond caused hrtimer/futex issue
Date: Tue, 24 Jul 2012 03:37:43 +0100 [thread overview]
Message-ID: <1343097463.5132.89.camel@deadeye.wl.decadent.org.uk> (raw)
In-Reply-To: <500DAB3F.30606@us.ibm.com>
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On Mon, 2012-07-23 at 12:51 -0700, John Stultz wrote:
> On 07/19/2012 01:48 PM, Christoph Biedl wrote:
> > John Stultz wrote...
> >
> >> Attached is the test case I used to reproduce and test the solution
> >> to the hard-hang deadlock.
> > I was wondering whether anybody managed to crash a virtualbox guest
> > using your program. No avail, using version 4.1.18 on the host and the
> > guest kernel running several 3.0.x (x < 38) kernels on both x32 and
> > x64, the guest utilies were stopped. Rather a fun fact I guess but I
> > wanted to let you know.
>
> I've been able to crash a kvm guest with an unpatched kernel with my
> test. The issue requires that the adding of the hrtimer causes the
> clockevent to be reprogrammed. This usually happens if there's no timers
> that expire sooner then the leapsecond timer. So if there are drivers
> that set frequent timers, or set timers right before the leapsecond, it
> may be difficult to trigger this issue.
>
> Lowering HZ or adding more vcpus might help if you really want to be
> able to trigger the issue.
[...]
Your test program also made Linux 3.2.23 (or it may have been .21)
lock-up for me in a KVM guest, while 3.2.24-rc1 seemed immune.
Ben.
--
Ben Hutchings
If more than one person is responsible for a bug, no one is at fault.
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next prev parent reply other threads:[~2012-07-24 2:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-17 7:05 John Stultz
2012-07-17 7:05 ` [PATCH 01/11] 3.2.x: ntp: Fix leap-second hrtimer livelock John Stultz
2012-07-17 7:05 ` [PATCH 02/11] 3.2.x: ntp: Correct TAI offset during leap second John Stultz
2012-07-17 7:05 ` [PATCH 03/11] 3.2.x: timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond John Stultz
2012-07-17 7:05 ` [PATCH 04/11] 3.2.x: time: Move common updates to a function John Stultz
2012-07-17 7:05 ` [PATCH 05/11] 3.2.x: hrtimer: Provide clock_was_set_delayed() John Stultz
2012-07-17 7:05 ` [PATCH 06/11] 3.2.x: timekeeping: Fix leapsecond triggered load spike issue John Stultz
2012-07-17 7:05 ` [PATCH 07/11] 3.2.x: timekeeping: Maintain ktime_t based offsets for hrtimers John Stultz
2012-07-17 7:05 ` [PATCH 08/11] 3.2.x: hrtimers: Move lock held region in hrtimer_interrupt() John Stultz
2012-07-17 7:05 ` [PATCH 09/11] 3.2.x: timekeeping: Provide hrtimer update function John Stultz
2012-07-17 7:05 ` [PATCH 10/11] 3.2.x: hrtimer: Update hrtimer base offsets each hrtimer_interrupt John Stultz
2012-07-17 7:05 ` [PATCH 11/11] 3.2.x: timekeeping: Add missing update call in timekeeping_resume() John Stultz
2012-07-17 7:10 ` [PATCH 00/11] 3.2-stable: Fix for leapsecond caused hrtimer/futex issue John Stultz
2012-07-19 20:48 ` Christoph Biedl
2012-07-23 19:51 ` John Stultz
2012-07-24 2:37 ` Ben Hutchings [this message]
2012-07-22 18:50 ` Ben Hutchings
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