oops BUG unable to handle kernel NULL point dereference IP io_ctl_check_crc

oops BUG unable to handle kernel NULL point dereference IP io_ctl_check_crc

[Chris Murphy]

https://bugzilla.kernel.org/show_bug.cgi?id=97991

A file system with no problems booting 4.0.1 and 3.9.7 kernels on
ancient i686 hardware. Btrfs check has no complaints. But it won't
boot 4.1.0.rc2 at all and explodes so spectacularly I can't really
capture anything.

The best I have so far is using rd.break=pre-mount, and manually
mounting the btrfs. No complaints. But the instant I try to write a
file: dmesg > dmesg.txt, I get a panic.

All I have at the moment is a photo until I can reproduce in a VM.

-- 
Chris Murphy

Re: oops BUG unable to handle kernel NULL point dereference IP io_ctl_check_crc

[Chris Murphy]

On Sat, May 9, 2015 at 12:34 AM, Chris Murphy <lists@colorremedies.com> wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=97991

OK it appears to be a 32bit kernel problem, as it happens in an x86_64
qemu/kvm VM.

But that same vm with the same version 64bit kernel doesn't exhibit the problem.

-- 
Chris Murphy

Re: oops BUG unable to handle kernel NULL point dereference IP io_ctl_check_crc

[Filipe David Manana]

On Sat, May 9, 2015 at 8:43 AM, Chris Murphy <lists@colorremedies.com> wrote:
> On Sat, May 9, 2015 at 12:34 AM, Chris Murphy <lists@colorremedies.com> wrote:
>> https://bugzilla.kernel.org/show_bug.cgi?id=97991
>
> OK it appears to be a 32bit kernel problem, as it happens in an x86_64
> qemu/kvm VM.
>
> But that same vm with the same version 64bit kernel doesn't exhibit the problem.

Sounds like it should have been fixed in rc3 by [1], the same trace
was reported recently [2].

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1d3c61c2eb3fe4f96d3192212f1bdcee49ea55aa
[2] http://www.spinics.net/lists/linux-btrfs/msg43754.html

>
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> Chris Murphy
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-- 
Filipe David Manana,

"Reasonable men adapt themselves to the world.
 Unreasonable men adapt the world to themselves.
 That's why all progress depends on unreasonable men."

Re: oops BUG unable to handle kernel NULL point dereference IP io_ctl_check_crc

[Chris Mason]

On 05/09/2015 03:43 AM, Chris Murphy wrote:
> On Sat, May 9, 2015 at 12:34 AM, Chris Murphy <lists@colorremedies.com> wrote:
>> https://bugzilla.kernel.org/show_bug.cgi?id=97991
> 
> OK it appears to be a 32bit kernel problem, as it happens in an x86_64
> qemu/kvm VM.
> 
> But that same vm with the same version 64bit kernel doesn't exhibit the problem.
> 

Yeah, the GFP mask patch in rc3 will fix it up.  Sorry for the hassle.

-chris