Messages in this thread | | | Date | Thu, 10 Jun 2010 17:06:34 -0700 (PDT) | From | alan <> | Subject | Re: Additional info on modpost segfault |
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On Fri, 11 Jun 2010, 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?
YES!
Thank you!
Now the big question is why does this compile on older versions of gcc?
This needs to get added into 2.6.35-rc2.
> > Signed-off-by: Krzysztof Haÿÿasa <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/ >
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