From: John Stultz <john.stultz@linaro.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Richard Cochran <richardcochran@gmail.com>,
Prarit Bhargava <prarit@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-fsdevel@vger.kernel.org
Subject: Re: BUG: NULL pointer dereference in shmem_evict_inode()
Date: Mon, 20 Aug 2012 18:46:05 -0700 [thread overview]
Message-ID: <5032E85D.8020404@linaro.org> (raw)
In-Reply-To: <20120821013123.GA12104@localhost>
On 08/20/2012 06:31 PM, Fengguang Wu wrote:
> On Mon, Aug 20, 2012 at 06:10:57PM -0700, John Stultz wrote:
>> On 08/20/2012 06:04 PM, Fengguang Wu wrote:
>>> Hi John,
>>>
>>> The below oops happens in v3.5..v3.6-rc2 and it's bisected down to commit
>>> 2a8c0883c ("time: Move xtime_nsec adjustment underflow handling timekeeping_adjust").
>>>
>>> However linux-next is working fine. Do you have any fixes not yet sent to Linus?
>> Yea, there's a fix pending in tip/timers/urgent
>> (4e8b14526ca7fb046a81c94002c1c43b6fdf0e9b) to catch crazy values
>> from settimeofday or the cmos clock that might overflow a ktime_t.
> That's great!
>
>> Out of curiosity, how are you triggering/reproducing this?
> I boot test lots of randconfig kernels in kvm, and this oops shows up
> several times in one ranconfig and some of the test boxes. I find it
> pretty hard to reproduce, but managed to bisect it down by counting
> 1000 good boots as bisect success and running dozens of KVM instances
> in parallel in several test boxes to speed up the progress. Here is one step:
Oof. That's an really impressive setup!
That said, if this happens only at boot up, and you don't have systems
with crazy cmos values, I'm not sure I see how commit
4e8b14526ca7fb046a81c94002c1c43b6fdf0e9b might fix this. So that's not
very reassuring.
As a tangent, I think this sort of big-data style testing is a really
great contribution, so thank you for setting up and doing all this work.
-john
next prev parent reply other threads:[~2012-08-21 1:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 1:04 BUG: NULL pointer dereference in shmem_evict_inode() Fengguang Wu
2012-08-21 1:10 ` John Stultz
2012-08-21 1:15 ` John Stultz
2012-08-21 1:40 ` Fengguang Wu
2012-08-21 1:49 ` John Stultz
2012-08-21 8:01 ` Fengguang Wu
2012-08-21 1:31 ` Fengguang Wu
2012-08-21 1:46 ` John Stultz [this message]
2012-08-21 1:58 ` Fengguang Wu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5032E85D.8020404@linaro.org \
--to=john.stultz@linaro.org \
--cc=a.p.zijlstra@chello.nl \
--cc=fengguang.wu@intel.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=prarit@redhat.com \
--cc=richardcochran@gmail.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).