Re: raid1 boot regression in 2.6.37 [bisected]

[Thomas Jarosch <thomas.jarosch@intra2net.com>]

On 03/28/2011 05:59 PM, Tejun Heo wrote:
>> Call Trace:
>>  [<c12dc808>] mutex_unlock+0x8/0x10
>>  [<c11c4451>] kobj_lookup+0xe1/0x140
>>  [<c11323b0>] ? exact_match+0x0/0x10
>>  [<c11331b8>] get_gendisk+0x98/0xb0
>>  [<c10e85aa>] __blkdev_get+0xca/0x320
>>  [<c10e8843>] blkdev_get+0x43/0x2c0
>>  [<c12de75d>] ? _raw_spin_unlock+0x1d/0x20
>>  [<c10e8b12>] blkdev_open+0x52/0x70
>>  [<c10bb12d>] __dentry_open+0x9d/0x240
>>  [<c10bb3c6>] nameidata_to_filp+0x66/0x80
>>  [<c10e8ac0>] ? blkdev_open+0x0/0x70
>>  [<c10c781f>] finish_open+0xaf/0x190
>>  [<c10c8a24>] ? do_path_lookup+0x44/0xe0
>>  [<c10c9920>] do_filp_open+0x210/0x6d0
>>  [<c10672e9>] ? lock_release_non_nested+0x59/0x2f0
>>  [<c12de75d>] ? _raw_spin_unlock+0x1d/0x20
>>  [<c10d47d8>] ? alloc_fd+0xb8/0xf0
>>  [<c10baf45>] do_sys_open+0x55/0xf0
>>  [<c10bb049>] sys_open+0x29/0x40
>>  [<c1002e9f>] sysenter_do_call+0x12/0x38
> 
> Hmmm... Weird.
> 
> * blkid seems to be looping in blkdev_open() repeatedly calling
>   md_open() which keeps returning -ERESTARTSYS.
> 
> * It triggered softlockup.  Even with -ERESTARTSYS looping, I can't
>   see how that would be possible.
> 
> Is this custom boot script?  If so, do you use RT priority in the
> script?

It's a normal dracut installation with an additional custom script
to trigger kernel raid auto detection via mdadm.
The custom script was part of the initial post.

I've also noticed another odd thing: On a HP Proliant ML110 G6 box,
which is quite fast / SMP, the box brings up the software
RAID successfully. The box is slow as hell and I can see a constant load
on a kernel process (could be "kworker", don't remember it exactly).
I'll try tomorrow if that is also related to the RAID subsystem
or something else turning it into a PDP11...

Thanks for your help so far!

Cheers,
Thomas