Messages in this thread | | | Date | Wed, 18 May 2022 10:36:04 -0700 | From | Josh Poimboeuf <> | Subject | Re: [PATCH] objtool: Fix symbol creation |
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On Wed, May 18, 2022 at 09:41:52AM +0200, Peter Zijlstra wrote: > +static int elf_update_symbol(struct elf *elf, struct section *symtab, > + struct section *symtab_shndx, struct symbol *sym) > { > - Elf_Data *data, *shndx_data = NULL; > - Elf32_Word first_non_local; > - struct symbol *sym; > - Elf_Scn *s; > - > - first_non_local = symtab->sh.sh_info; > - > - sym = find_symbol_by_index(elf, first_non_local); > - if (!sym) { > - WARN("no non-local symbols !?"); > - return first_non_local; > - } > + Elf_Data *symtab_data = NULL, *shndx_data = NULL; > + Elf64_Xword entsize = symtab->sh.sh_entsize; > + Elf32_Word shndx = sym->sec->idx;
So if it's a global UNDEF symbol then I think 'sym->sec' can be NULL and this blows up?
> + for (;;) { > + /* get next data descriptor for the relevant sections */ > + symtab_data = elf_getdata(s, symtab_data); > + if (t) > + shndx_data = elf_getdata(t, shndx_data); > + > + /* end-of-list */ > + if (!symtab_data) { > + /* if @idx == 0, it's the next contiguous entry, create it */ > + if (!idx) { > + void *buf;
Could just do the "index out of range warning" here to reduce the indentation level.
> + /* setup extended section index magic and write the symbol */ > + if (shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) {
> + sym->sym.st_shndx = shndx; > + if (!shndx_data) > + shndx = 0;
I think this '0' is SHN_UNDEF?
Also shouldn't 'sym->sym.st_shndx' get the same value?
-- Josh
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