On Thu, Jun 23, 2022 at 12:51:08PM -0600, Keith Busch wrote: > On Thu, Jun 23, 2022 at 02:29:13PM -0400, Eric Farman wrote: > > On Fri, 2022-06-10 at 12:58 -0700, Keith Busch wrote: > > > From: Keith Busch <kbusch@xxxxxxxxxx> > > > > > > Use the address alignment requirements from the block_device for > > > direct > > > io instead of requiring addresses be aligned to the block size. > > > > Hi Keith, > > > > Our s390 PV guests recently started failing to boot from a -next host, > > and git blame brought me here. > > > > As near as I have been able to tell, we start tripping up on this code > > from patch 9 [1] that gets invoked with this patch: > > > > > for (k = 0; k < i->nr_segs; k++, skip = 0) { > > > size_t len = i->iov[k].iov_len - skip; > > > > > > if (len > size) > > > len = size; > > > if (len & len_mask) > > > return false; > > > > The iovec we're failing on has two segments, one with a len of x200 > > (and base of x...000) and another with a len of xe00 (and a base of > > x...200), while len_mask is of course xfff. > > > > So before I go any further on what we might have broken, do you happen > > to have any suggestions what might be going on here, or something I > > should try? > > Thanks for the notice, sorry for the trouble. This check wasn't intended to > have any difference from the previous code with respect to the vector lengths. > > Could you tell me if you're accessing this through the block device direct-io, > or through iomap filesystem? If using iomap, the previous check was this: unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); unsigned int align = iov_iter_alignment(dio->submit.iter); ... if ((pos | length | align) & ((1 << blkbits) - 1)) return -EINVAL; And if raw block device, it was this: if ((pos | iov_iter_alignment(iter)) & (bdev_logical_block_size(bdev) - 1)) return -EINVAL; The result of "iov_iter_alignment()" would include "0xe00 | 0x200" in your example, and checked against 0xfff should have been failing prior to this patch. Unless I'm missing something...