Bug#597563: grub-common: grub-probe segfaults scanning lvm devices

[Matthew Gabeler-Lee]

On 1/9/2011 16:57, NeilBrown wrote:
> Simply running
>     mdadm --zero-superblock /dev/sdb
>
> should fix it.
Well, that doesn't work very well: "mdadm: Couldn't open /dev/sdb for write 
- not zeroing" ... strace reveals that mdadm is trying to open it O_EXCL, 
which I presume is why it's not working ... I presume I'd have to reboot to 
single user mode and stop the LVM and possibly MD stuff in order for that to 
work, which might then require booting from a rescue cd to do it.

So I backed up the contents of the end of the disk in case I screwed up, and 
then zerro'd it with dd (nervous nervous).  I double-checked things with 
mdadm --examine to double-check I had cleared the stray superblock and not 
damaged the one in sdb3, and that looks OK

After doing that, the version of grub-probe that was crashing before appears 
to work properly, and the trunk version of grub-probe no longer spits out 
the warning/error.  I then upgraded the debian package to the latest version 
in testing (since I'd been using an old version where I could work around 
the problems), and let it run the grub-install on all 4 disks, and that 
proceeded without errors.  Hooray :)

Thank you folks for your help solving this!

-- 
	-Matt
"Reality is that which, when you stop believing in it, doesn't go away".
                 -- Philip K. Dick
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