Re: PROBLEM: Kernel BUG with raid5 soft + Xen + DRBD - invalid opcode

[Shaohua Li <shli@kernel.org>]

On Fri, Dec 23, 2016 at 07:25:56PM +0100, MasterPrenium wrote:
> Hello Guys,
> 
> I've having some trouble on a new system I'm setting up. I'm getting a kernel BUG message, seems to be related with the use of Xen (when I boot the system _without_ Xen, I don't get any crash).
> Here is configuration :
> - 3x Hard Drives running on RAID 5 Software raid created by mdadm
> - On top of it, DRBD for replication over another node (Active/passive cluster)
> - On top of it, a BTRFS FileSystem with a few subvolumes
> - On top of it, XEN VMs running.
> 
> The BUG is happening when I'm making "huge" I/O (20MB/s with a rsync for example) on the RAID5 stack.
> I've to reset system to make it work again.

what did you mean 'huge' I/O (20M/s)? Is it possible you can reproduce the
issue with a raw raid5 raid? It would be even better if you can give me a fio
job file with the issue, so I can easily debug it.

also please check if upstream patch (e8d7c33 md/raid5: limit request size
according to implementation limits) helps.

Thanks,
Shaohua