Re: [Bug 100491] New: Oops under bitmap_start_sync [md_mod] at boot

[Austin S Hemmelgarn <ahferroin7@gmail.com>]

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On 2015-06-28 16:53, Sami Liedes wrote:
> On Thu, Jun 25, 2015 at 09:02:45PM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
>> https://bugzilla.kernel.org/show_bug.cgi?id=100491
>>
>>              Bug ID: 100491
>>             Summary: Oops under bitmap_start_sync [md_mod] at boot
> [...]
>> Reading all physical valumes.  This may take a while...
>> Found volume group "rootvg" using metadata type lvm2
>> device-mapper: raid: Device 0 specified for rebuild: Clearing superblock
>> md/raid1:mdX: active with 1 out of 2 mirrors
>> mdX: invalid bitmap file superblock: bad magic
>> md-cluster module not found.
>> mdX: Could not setup cluster service (256)
>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000100
>> IP: [<ffffffff8159e4a9>] _raw_spin_lock_irq+0x29/0x70
>> PGD 0
>> Oops: 0002 [#1] PREEMPT SMP
> [...]
>
> I'm marking this as a regression in bugzilla, since this seems to
> prevent booting on 4.1.0 at least in certain circumstances (namely
> those which I have; I wonder if any raid1 recovery works?) while 4.0.6
> boots correctly.
I can confirm having the same issue with the MD code being used through 
dm-raid.
>
> I bisected this down to one of four commits. Well, assuming that the
> problem was caused by changes in drivers/md; a fair assumption, I
> think. The commits are:
>
> $ git bisect view --oneline
> f9209a3 bitmap_create returns bitmap pointer
> 96ae923 Gather on-going resync information of other nodes
> 54519c5 Lock bitmap while joining the cluster
> b97e9257 Use separate bitmaps for each nodes in the cluster
My own bisect turned up the same set of commits, although I wouldn't 
have the time to go any further with it until next weekend.
>
> The crash happens whether or not CONFIG_MD_CLUSTER is enabled.
Again, same here.



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