Re: BUG: Bad page map in process udevd (anon_vma: (null)) in 2.6.38-rc4

[Eric W. Biederman]

Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:

> On Thu, Feb 17, 2011 at 10:57 AM, Eric W. Biederman
> <ebiederm@xxxxxxxxxxxx> wrote:
>>
>> fedora 14
>> ext4 on all filesystems
>
> Your dmesg snippets had ext3 mentioned, though:
>
>   <6>EXT3-fs (sda1): recovery required on readonly filesystem
>   <6>EXT3-fs (sda1): write access will be enabled during recovery
>   <6>EXT3-fs: barriers not enabled
>   ..
>   <6>EXT3-fs (sda1): recovery complete
>   <6>EXT3-fs (sda1): mounted filesystem with ordered data mode
>   <6>dracut: Mounted root filesystem /dev/sda1
>
> not that I see that it should matter, but there's been some bigger
> ext3 changes too (like the batched discard).
>
> I don't really think ext3 is the issue, though.
>
>> I was about to say this happens with DEBUG_PAGEALLOC enabled but it
>> appears that options keeps eluding my fingers when I have a few minutes
>> to play with it. ÂPerhaps this time will be the charm.
>
> Please do. You seem to be much better at triggering it than anybody
> else. And do the DEBUG_LIST and DEBUG_SLUB_ON things too (even if the
> DEBUG_LIST thing won't catch list_move())

Interesting.  I just got this with DEBUG_PAGEALLOC
It looks like something in DEBUG_PAGEALLOC is interfering with taking a
successful crashdump.

Given how many network namespaces I create and destroy this might be a
code path I exercise more than most people.

BUG: unable to handle kernel paging request at ffff8801adf8d760
IP: [<ffffffff8140c7ca>] unregister_netdevice_queue+0x3a/0xb0
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/system/cpu/cpu7/cache/index2/shared_cpu_map
Stack:
Call Trace:
Code: 24 08 48 89 fb 49 89 f4 e8 f4 c8 00 00 85 c0 74 6d 4d 85 e4 74 3b 48 8b 93 a0 00 00 00 48 8b 83 a8 00 00 00 48 8d bb a0 00 00 00 <48> 89 42 08 48 89 10 4c 89 e2 49 8b 74 24 08 e8 32 75 e7 ff 48 
RIP  [<ffffffff8140c7ca>] unregister_netdevice_queue+0x3a/0xb0
CR2: ffff8801adf8d760

Eric
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