r286727 breaks geom_md.ko loading

[Gleb Smirnoff]

On Wed, Sep 16, 2015 at 04:57:39PM +0300, Konstantin Belousov wrote:
K> On Wed, Sep 16, 2015 at 04:50:03PM +0300, Gleb Smirnoff wrote:
K> > On Wed, Sep 16, 2015 at 04:42:49PM +0300, Konstantin Belousov wrote:
K> > K> On Wed, Sep 16, 2015 at 04:15:15PM +0300, Gleb Smirnoff wrote:
K> > K> > On Wed, Sep 16, 2015 at 08:10:05AM +0300, Konstantin Belousov wrote:
K> > K> > K> >   There is regression after r286727. Our dynamic kernel linker doesn't
K> > K> > K> > support weak symbols, so the geom_md.ko can no longer be loaded dynamically
K> > K> > K> > neither from loader nor at runtime. Having it statically in kernel is
K> > K> > K> > the only working option.
K> > K> > K> 
K> > K> > K> Perhaps, something could be fixed in the dynamic linker ?
K> > K> > K> 
K> > K> > K> I checked both i386 and amd64, and on both arches I can load geom_md.ko.
K> > K> > K> On the other hand, I do not use preloaded mfs images.  Can you explain
K> > K> > K> how to reproduce the issue, and what linker is affected ?  Note that we
K> > K> > K> have two kernel dynamic linkers, one is used on amd64 and mips, second one
K> > K> > K> is for all other architectures.
K> > K> > 
K> > K> > To reproduce you need just a vanilla head, a kernel that doesn't have
K> > K> > 'device md' in it, and run kldload geom_md.ko. Does that work for you?
K> > K> 
K> > K> Yes, it does, both on amd64 and i386.  You did not said which architecture
K> > K> exposes your problem.  Post your kernel config.
K> > 
K> > It is amd64. Here is config.
K> 
K> > options 	MD_ROOT			# MD is a potential root device
K> It is MD_ROOT which is problematic, it seems.  I will take a look into
K> linker.

Yes, sorry for not being verbose enough. Kernel must not have 'device md'
and must have 'options MD_ROOT'.

-- 
Totus tuus, Glebius.