Re: RAID5 lockup with AMCC440 and async-tx

[Wolfgang Denk <wd@denx.de>]

Dear Dale,

in message <8a24fb800710010216m21cd7734p4c19df1aa7dd5564@mail.gmail.com> you wrote:
> 
> I have a board with an AMCC440 processor, running RAID5 using the
> async-tx interface. In general, it works well, but I have found a test
> case that consistently causes a hard lockup of the entire system.

Please make sure to use latest code - we found a bug recently.

> What makes this case odd is that I have only been able to generate it
> when accessing disks that are on two separate HBAs - in my case
> mpt-fusion based SAS HBAs. Once two HBAs are in use, the bug is
> trivial to repeat. I simply create a RAID5 using disks from each HBA,
> wait for it to resync, and then run

We saw similar problems, in our case they showed up only with a large
number of disks in combination with big kernel pages sizes (64 kB).

> Any pointers on how to debug this? It feels like a race condition of
> some description, but any serial port printing I enable causes the
> problem to go away, and I can't print silently to /var/log/messages as
> the system hangs before it can flush.

See above - please try current code.

Best regards,

Wolfgang Denk

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