Re: Strange crash on Dell R720xd

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