From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Brown <neilb-IBi9RG/b67k@public.gmane.org>
Subject: Re: dracut is too "clever" at identifying modules to exclude.
Date: Tue, 13 Oct 2015 07:30:37 +1100
Message-ID: <87vbabzv6a.fsf@notabene.neil.brown.name>
References: <20150409140840.0bb6d59d@notabene.brown> <87r3l023ha.fsf@notabene.neil.brown.name> <561BD1E9.5010007@redhat.com>
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To: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, trenn-IBi9RG/b67k@public.gmane.org
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Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> writes:

> On 12.10.2015 05:02, Neil Brown wrote:
>>=20
>> 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.
>>=20
>> As a particular instance this happen when the root filesystem is on
>> RAID0.  The 'raid0.ko' module is not included and boot fails.
>>=20
>> https://bugzilla.opensuse.org/show_bug.cgi?id=3D935993
>>=20
>> This only happens when 'host-only' is selected (which is the default for
>> openSUSE).
>>=20
>> the modules.d/90mdraid/module-setup.sh code calls
>>=20
>>     instmods =3Ddrivers/md
>>=20
>> instmods calls
>>    module_is_host_only "raid0"
>> and this incorrectly fails.
>>=20
>> If raid0.ko didn't have any alias this would succeed, but it does.
>>=20
>> $ 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

>
>>=20
>> However these aliases don't appear in any modalias file in /sys/devices,
>> in /proc/crypto, or in /proc/modules.
>>=20
>> Maybe you could parse /proc/mdstat..
>>=20
>> if [ -f /proc/mdstat ]; then
>>   while read _d _c _a _m _x; do
>>    if [ "$_c" =3D ':' -a "$_a" =3D 'active' ]; then
>>       host_modalias["md-$_m"]=3D1
>>    fi
>>   done < /proc/mdstat
>> fi
>>=20
>> but it all seems rather fragile.  There are probably other modules that
>> might miss out accidentally. dm?
>>=20
>> Do we really need the host_modalias stuff?
>>=20
>> Thanks,
>> NeilBrown
>>=20

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