Hi Mike, Paul's AFK so I tried the patch you sent. Mike Snitzer <snitzer@xxxxxxxxxx> writes: > On Thu, Mar 29 2018 at 4:39am -0400, > Paul Mackerras <paulus@xxxxxxxxxx> wrote: >> Since commit 8d47e65948dd ("dm mpath: remove unnecessary NVMe >> branching in favor of scsi_dh checks", 2018-03-05), upstream kernels >> fail to boot on my POWER8 box which has multipath SCSI disks. The >> host adapters are IPR and the userspace is CentOS 7. ... > > Please try this patch, it'll likely fix your issues: > > diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c > index dbddcdc5a4ec..746dd8a75b4a 100644 > --- a/drivers/md/dm-mpath.c > +++ b/drivers/md/dm-mpath.c > @@ -887,7 +887,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps > > q = bdev_get_queue(p->path.dev->bdev); > attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); > - if (attached_handler_name) { > + if (attached_handler_name || m->hw_handler_name) { > INIT_DELAYED_WORK(&p->activate_path, activate_path_work); > r = setup_scsi_dh(p->path.dev->bdev, m, attached_handler_name, &ti->error); > if (r) { And it does indeed fix the problem. The system boots happily with no warnings. If you like here's a: Tested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Any prospect of getting that patch to Linus before the 4.16 release? Yes I realise that's in ~36 hours :) cheers