lkml.org 
[lkml]   [2010]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Additional info on modpost segfault
On Fri, Jun 11, 2010 at 01:42:47PM -0700, H. Peter Anvin wrote:
> Michal, are you sending this to Linus?

I'll, once Linus takes another pull request I sent a couple of hours
ago. Thanks for the patch Krzysztof!

Michal

>
> -hpa
>
>
> On 06/10/2010 04:08 PM, Krzysztof Halasa wrote:
> > Alan <alan@clueserver.org> writes:
> >
> >> program: /home/alan/GitTrees/linux-2.6-mid-ref/scripts/mod/modpost -o
> >> Module.symvers -S vmlinux.o
> >>
> >> Program received signal SIGSEGV, Segmentation fault.
> >
> > It just hit me.
> > It's the offset calculation in reloc_location() which overflows:
> > return (void *)elf->hdr + sechdrs[section].sh_offset +
> > (r->r_offset - sechdrs[section].sh_addr);
> >
> > E.g. for the first rodata r entry:
> > r->r_offset < sechdrs[section].sh_addr
> > and the expression in the parenthesis produces 0xFFFFFFE0 or something
> > equally wise.
> >
> > Does the attached patch fix it?
> >
> > Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
> >
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -1317,8 +1317,8 @@ static unsigned int *reloc_location(struct elf_info *elf,
> > Elf_Shdr *sechdrs = elf->sechdrs;
> > int section = sechdr->sh_info;
> >
> > return (void *)elf->hdr + sechdrs[section].sh_offset +
> > - (r->r_offset - sechdrs[section].sh_addr);
> > + r->r_offset - sechdrs[section].sh_addr;
> > }
> >
> > static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2010-06-12 00:53    [from the cache]
©2003-2011 Jasper Spaans