On Thursday March 22, dan.j.williams@xxxxxxxxx wrote: > > Not a cfq failure, but I have been able to reproduce a different oops > at array stop time while i/o's were pending. I have not dug into it > enough to suggest a patch, but I wonder if it is somehow related to > the cfq failure since it involves congestion and drives going away: Thanks. I know about that one and have a patch about to be posted which should fix it. But I don't completely understand it. When a raid5 array shuts down, it clears mddev->private, but doesn't clean q->backing_dev_info.congested_fn. So if someone tries to call that congested_fn, it will try to dereference mddev->private and Oops. Only by the time that raid5 is shutting down, no-one should have a reference to the device any more, and no-one should be in a position to call congested_fn !! Maybe pdflush is just trying to sync the block device, even though there is no dirty date .... dunno.... But I don't think it is related to the cfq problem as this one is only a problem when the array is being stopped. Thanks, NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
