On Mon, Jun 15, 2026 at 05:42:42PM +0000, Dr. David Alan Gilbert wrote: > * Keith Busch ([email protected]) wrote: > > On Mon, Jun 15, 2026 at 04:37:39PM +0000, Dr. David Alan Gilbert wrote: > > > Hi Keith, > > > Thanks for the patch, alas it doesn't seem to be helping here; > > > the first warn is still the same > > > and it still hangs the test process hard and eventually BUGs at > > > > > > void blk_mq_end_request(struct request *rq, blk_status_t error) > > > { > > > if (blk_update_request(rq, error, blk_rq_bytes(rq))) > > > BUG(); > > > > Oh, that was not expected. > > > > What is the dma alignment requirement of your backing devices? You can > > find the attribute for sda at /sys/block/sda/queue/dma_alignment. I'm > > expecting 511, but just want to double check. > > Yeh looks like it: > /sys/block/sda/queue/dma_alignment:511 > /sys/block/sdb/queue/dma_alignment:511 > > all of the lvm also looks like it is.
Thanks for confirming. I'm struggling to see how you're getting there with your reproducer with the proposal included. I can see other short comings with preadv or really large pread's, but not with a 4k pread. For those other issues this patch can fix it: https://lore.kernel.org/linux-block/[email protected]/ It is currently staged for upstream, so hasn't landed yet. But again, I don't think those conditions apply to what you're seeing, but worth a shot on top of the previous proposal to use byte units instead of sectors. In the meantime, since I so far can't reproduce this after including my previous proposal, I may have to request trying out a debug patch to get some more visibility on what's happening if that's okay.
