From mboxrd@z Thu Jan 1 00:00:00 1970 From: Harald Hoyer Subject: Re: dracut is too "clever" at identifying modules to exclude. Date: Fri, 13 Nov 2015 13:37:53 +0100 Message-ID: <5645D9A1.3040304@redhat.com> References: <20150409140840.0bb6d59d@notabene.brown> <87r3l023ha.fsf@notabene.neil.brown.name> <561BD1E9.5010007@redhat.com> <87vbabzv6a.fsf@notabene.neil.brown.name> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87vbabzv6a.fsf-wvvUuzkyo1HefUI2i7LXDhCRmIWqnp/j@public.gmane.org> Sender: initramfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Neil Brown , trenn-IBi9RG/b67k@public.gmane.org Cc: initramfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 12.10.2015 22:30, Neil Brown wrote: > Harald Hoyer writes: > >> On 12.10.2015 05:02, Neil Brown wrote: >>> >>> If I have booted a kernel with md/raid built in (no modules) and >>> I use dracut to build the initramfs for a different kernel which >>> has the md code compiled as separate modules, then it does not include >>> the required md modules in the initramfs. >>> >>> As a particular instance this happen when the root filesystem is on >>> RAID0. The 'raid0.ko' module is not included and boot fails. >>> >>> https://bugzilla.opensuse.org/show_bug.cgi?id=935993 >>> >>> This only happens when 'host-only' is selected (which is the default for >>> openSUSE). >>> >>> the modules.d/90mdraid/module-setup.sh code calls >>> >>> instmods =drivers/md >>> >>> instmods calls >>> module_is_host_only "raid0" >>> and this incorrectly fails. >>> >>> If raid0.ko didn't have any alias this would succeed, but it does. >>> >>> $ modinfo -F alias raid0 >>> md-level-0 >>> md-raid0 >>> md-personality-2 >> >> Huh? Is the module not loaded? > > No, because the running kernel has "md/raid built in (no modules)". > > Thanks, > NeilBrown > >> >>> >>> However these aliases don't appear in any modalias file in /sys/devices, >>> in /proc/crypto, or in /proc/modules. >>> >>> Maybe you could parse /proc/mdstat.. >>> >>> if [ -f /proc/mdstat ]; then >>> while read _d _c _a _m _x; do >>> if [ "$_c" = ':' -a "$_a" = 'active' ]; then >>> host_modalias["md-$_m"]=1 >>> fi >>> done < /proc/mdstat >>> fi >>> >>> but it all seems rather fragile. There are probably other modules that >>> might miss out accidentally. dm? >>> >>> Do we really need the host_modalias stuff? >>> >>> Thanks, >>> NeilBrown >>> Interesting... so we have to blow up the initramfs with the entire drivers/md in the case, where you switch from "compiled in" to "not compiled in".. I guess that happens not that often, so better be safe than sorry.