From: John Stultz <johnstul@us.ibm.com>
To: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Cc: 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: Mon, 23 Jul 2012 12:51:27 -0700 [thread overview]
Message-ID: <500DAB3F.30606@us.ibm.com> (raw)
In-Reply-To: <1342730535@msgid.manchmal.in-ulm.de>
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.
> All real hardware tested, including a dockstar on armel, crashed as
> predicted, while 3.0.38-rc1 was immune.
Great to hear!
thanks
-john
next prev parent reply other threads:[~2012-07-23 19:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-17 7:05 [PATCH 00/11] 3.2-stable: Fix for leapsecond caused hrtimer/futex issue 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 [this message]
2012-07-24 2:37 ` Ben Hutchings
2012-07-22 18:50 ` Ben Hutchings
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