On Wed, Aug 03 2022 at 2:29P -0400, Nathan Huckleberry <nhuck@xxxxxxxxxx> wrote: > The previous patch had a bug when hash verification failed in the > tasklet. This happened because the tasklet has already advanced the > bvec_iter when it falls back to the work-queue implementation. When the > work-queue job begins running, it attempts to restart verifiying at > block i, but the bvec_iter is at block i+1. > > This causes several failures, the most noticeable is that there are not > enough bytes in the bvec_iter to finish verification. Since there are > not enough bytes to finish, the work queue gets stuck in an infinite > loop in verity_for_io_block. > > To fix this, we can make a local copy of the bvec_iter struct in > verity_verify_io. This requires that we restart verification from the > first block when deferring to a work-queue rather than starting from the > last block verified in the tasklet. > > This patch also fixes what appears to be a memory leak when FEC is > enabled. The call to verity_fec_init_io should only be made if we are > in a work-queue since a tasklet does not use FEC and is unable to free > the memory. > > Signed-off-by: Nathan Huckleberry <nhuck@xxxxxxxxxx> Thanks for the detailed header, helped me appreciate the details of your incremental fixes. I folded your fixes in to the original commit that adds the "try_verify_in_tasklet" feature. I also layered on some verity_verify_io() optimizations in new commits. Lastly, I added the use of WQ_HIGHPRI if "try_verify_in_tasklet" feature is used. The end result passes Milan's testsuite with and without --use-tasklets. I've staged the changes in linux-next, see: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=for-next There is a chance I'll send another 6.0 pull request to Linus with these changes tomorrow. We've done quite a bit of work here (_before_ the 6.0 merge window opened) so I do think it'd be best to get these changes upstream sooner rather than later. If anyone disagrees with sending these changes upstream now please speak-up! Thanks, Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel
