Re: Strange crash on Dell R720xd

From: Laurent CARON
Date: Wed Oct 17 2012 - 03:31:15 EST


On Tue, Oct 16, 2012 at 10:58:49AM -0700, Dan Williams wrote:
> I think this may be a bug in __raid_run_ops that is only possible when
> raid offload and CONFIG_MULTICORE_RAID456 are enabled. I'm thinking
> the descriptor is completed and recycled to another requester in the
> space between these two events:
>
> ops_run_compute();
>
> /* terminate the chain if reconstruct is not set to be run */
> if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
> async_tx_ack(tx);
>
> ...don't use the experimental CONFIG_MULTICORE_RAID456 even if you
> leave IOAT DMA disabled. A rework of the raid operation dma chaining
> is in progress, but may not be ready for a while.

Hi,

I usually don't use CONFIG_MULTICORE_RAID456 as it proved to be sluggish
and/or unstable in my experience, so I should be pretty safe letting I/O
AT DMA disabled for now on those bosex.

Thanks

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