Messages in this thread | | | Date | Wed, 06 Jun 2012 12:14:33 +0100 | From | "Jan Beulich" <> | Subject | Re: [PATCH] x86,nmi: Fix section mismatch warnings on 32-bit |
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>>> On 05.06.12 at 20:35, Don Zickus <dzickus@redhat.com> wrote: > On Tue, Jun 05, 2012 at 04:42:20PM +0100, Jan Beulich wrote: >> >>> On 05.06.12 at 16:47, Don Zickus <dzickus@redhat.com> wrote: >> > On Tue, Jun 05, 2012 at 09:12:13AM +0100, Jan Beulich wrote: >> >> So before applying a change like this, I'd really like to understand >> >> the issue itself. Could you simply attach the nmi_selftest.o file >> >> that you get without your patch here (and indicate which >> >> upstream version or revision the corresponding source file was >> >> from, to be able to re-construct what the compiler actually did)? >> > >> > I could but it might be easier for you to re-create it on your end. >> > Using gcc-4.4.4 on an x86_64 box and v3.5-rc1, I just set >> > CONFIG_DEBUG_NMI_SELFTEST to 'y' and compile with >> > >> > make ARCH=i386 O=out/i686 >> > >> > and it easily reproduces for me. >> >> I don't think I have a plain 4.4.4 around anywhere, nor is it clear >> whether you used a plain one (and how it was configured). For >> tricky, highly version dependent things like this (where a compiler >> bug also can't be excluded), having the _exact_ object file the >> problem was seen with would be much easier than trying to hunt >> down a compiler version that I can reproduce this with. > > I didn't think it would be compiler dependent as I do not know what > compiler the reporter was using. I used a RHEL-6 4.4.4 compiler (which > you probably don't have :^) ).
Indeed, somehow I failed to see the obvious - it's commit 72b3fb24713755cf9740b403e95aa67ceedf3509 that causes these problems. Instantiating static data like this just doesn't play with any of the pointers passed being into .init.*.
I'd suggest either open coding register_nmi_handler() (with the static data put into __initdata), or further abstracting it by allowing an optional fifth argument (specifying the section annotation if needed).
Jan
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