On Wed, 03 Jun 2015 17:57:43 -0400 Jes Sorensen [off-list ref]
wrote:

NeilBrown [off-list ref] writes:

quoted

On Wed, 03 Jun 2015 16:20:21 -0400 Jes Sorensen [off-list ref]
wrote:

quoted

Neil,

I was running testing on the current 4.1-rc6 tree (Linus' top of trunk
8cd9234c64c584432f6992fe944ca9e46ca8ea76) and I am seeing the following
OOPS which is reproducible.

It shows up when running the mdadm test suite, 07changelevelintr to be
specific.

Is this something you have seen?

Cheers,
Jes

------------[ cut here ]------------
kernel BUG at drivers/md/raid5.c:5391!

No, I haven't seen that.  And I've been running the test suite quite a bit
lately.

Can you get it to print out the relevant numbers?  Include
readpos/writepos/safepos too.

This enough? Let me know if you need more.

I suspect this started happening with the changes that went in between
4.1-rc5 and 4.1-rc6. I will try to bisect it tomorrow.

Cheers,
Jes

mddev->dev_sectors: 0x9800, reshape_sectors: 0x0200 stripe_addr: fffffffffffffdff, sector_nr 0, readpos 511, writepos -513, safepos 512

Those negative numbers look VERY suspicious.
I'm actually on leave this week so I won't be looking at it any more, but
I'll see what I can find on Monday.
Thanks,
NeilBrown