Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm

Adam Borowski
2016-11-29T17:38:13Z

On Tue, Nov 29, 2016 at 07:27:12AM -0800, Linus Torvalds wrote:
> On Nov 29, 2016 5:51 AM, "Adam Borowski" <kilobyte@angband.pl> wrote:
> > >
> > > (a) tested
> >
> > By many people.
>
> No.
>
> I've tested the build *without* this, and it works fine.

Michal mentioned "why", let's try "where".

I have no idea what setup is required to trigger the problem, but here's a
simple sufficient one:

Current Debian unstable, amd64.
git reset --hard v4.9-rc7
git revert cd3caefb
make defconfig
CONFIG_MODVERSIONS=y
(in my case) CONFIG_BTRFS_FS=y (so I can boot)
enable a module for testing, I used CONFIG_EXT4_FS=m
make bindeb-pkg
dpkg -i linux-image_XXXXX.deb

modprobe ext4
[ 63.779490] jbd2: no symbol version for memcpy
[ 63.779492] jbd2: Unknown symbol memcpy (err -22)
[ 63.779550] jbd2: no symbol version for phys_base
[ 63.779551] jbd2: Unknown symbol phys_base (err -22)
[ 63.779561] jbd2: no symbol version for memset
[ 63.779562] jbd2: Unknown symbol memset (err -22)

Not sure which piece of toolchain matters here, someone said binutils.
In that case, Fedora ships 2.26.1-1.fc25, they were frozen so couldn't
update. Debian is at 2.27.51.20161127-1, Gentoo at 2.27, same for Arch,
OpenSUSE; Ubuntu at 2.27.51.20161124-1.

Thus, if it's indeed binutils, you'll see the breakage as soon as Fedora
recovers from the freeze.

Meow!
--
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