Re: modinfo must show real module info, not context if filename set

[Alexey Gladkov <gladkov.alexey@gmail.com>]

On Wed, Feb 26, 2020 at 11:36:00AM -0800, Lucas De Marchi wrote:
> On Wed, Feb 26, 2020 at 10:33 AM Alexey Gladkov
> <gladkov.alexey@gmail.com> wrote:
> >
> > On Wed, Feb 26, 2020 at 04:53:45AM +0200, Denis Kaganovich wrote:
> > > After commit e7e2cb61fa9f1db3429d91ef6accff549500d268, even if real filename
> > > passed - modinfo show info from context (so, I got built-in info from
> > > running
> > > kernel, but asking for new kernel's external module). This behaviour
> > > unobvious
> > > and incompatible with pre-v27. Simple use fake context for filename - IMHO
> > > much less ugly then current results.
> >
> > Can you give an example of this misbehavior ?
> >
> > I have a two kernel directories (generic and current) with
> > modules.builtin.modinfo:
> >
> > $ ls -1 /lib/modules/{5.2.0-generic,`uname -r`}/modules.builtin.modinfo
> > /lib/modules/5.2.0-generic/modules.builtin.modinfo
> > /lib/modules/5.2.0-current/modules.builtin.modinfo
> >
> > The ext4 module is built into both:
> >
> > $ tr '\0' '\n' < /lib/modules/`uname -r`/modules.builtin.modinfo |grep ^ext4.description
> > ext4.description=Fourth Extended Filesystem
> >
> > $ tr '\0' '\n' < /lib/modules/5.2.0-generic/modules.builtin.modinfo |grep ^ext4.description
> > ext4.description=Fourth Extended Filesystem
> >
> > Now I have build this module separately and put it into the tree:
> 
> that's why you don't have this problem. If you just build a new
> ext4.ko module and give it
> in the command line without putting it into the tree, then this
> problem would be triggered.

Ouch, I see. The phrase "new kernel's external module" confused me because
usually the modules for the new kernel are in the tree. My bad.

> $ ~/p/kmod/tools/modinfo fs/ext4/ext4.ko
> filename:       /home/ldmartin/p/gfx-internal/drm-intel-internal/fs/ext4/ext4.ko
> modinfo: ERROR: could not get modinfo from 'ext4': No such file or directory
> 
> $ modinfo fs/ext4/ext4.ko
> filename:       /home/ldmartin/p/gfx-internal/drm-intel-internal/fs/ext4/ext4.ko
> softdep:        pre: crc32c
> license:        GPL
> description:    Fourth Extended Filesystem
> author:         Remy Card, Stephen Tweedie, Andrew Morton, Andreas
> Dilger, Theodore Ts'o and others
> alias:          fs-ext4
> alias:          ext3
> alias:          fs-ext3
> alias:          ext2
> alias:          fs-ext2
> depends:        mbcache,jbd2
> retpoline:      Y
> intree:         Y
> name:           ext4
> vermagic:       5.4.17+ SMP preempt mod_unload
> 
> Lucas De Marchi

-- 
Rgrds, legion