On Fri, Nov 23, 2012 at 07:35:36PM +0900, satoru takeuchi wrote: > Hi, > > 2012/11/22 Greg Kroah-Hartman <gre...@linuxfoundation.org>: > > 3.6-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Rusty Russell <ru...@rustcorp.com.au> > > > > commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47 upstream. > > > > Masaki found and patched a kallsyms issue: the last symbol in a > > module's symtab wasn't transferred. This is because we manually copy > > the zero'th entry (which is always empty) then copy the rest in a loop > > starting at 1, though from src[0]. His fix was minimal, I prefer to > > rewrite the loops in more standard form. > > > > There are two loops: one to get the size, and one to copy. Make these > > identical: always count entry 0 and any defined symbol in an allocated > > non-init section. > > > > This bug exists since the following commit was introduced. > > module: reduce symbol table for loaded modules (v2) > > commit: 4a4962263f07d14660849ec134ee42b63e95ea9a > > > > LKML: http://lkml.org/lkml/2012/10/24/27 > > Reported-by: Masaki Kimura <masaki.kimura...@hitachi.com> > > Signed-off-by: Rusty Russell <ru...@rustcorp.com.au> > > Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> > > > > --- > > kernel/module.c | 27 ++++++++++++++++----------- > > 1 file changed, 16 insertions(+), 11 deletions(-) > > > > --- a/kernel/module.c > > +++ b/kernel/module.c > > @@ -2273,12 +2273,17 @@ static void layout_symtab(struct module > > src = (void *)info->hdr + symsect->sh_offset; > > nsrc = symsect->sh_size / sizeof(*src); > > > > + /* strtab always starts with a nul, so offset 0 is the empty > > string. */ > > + strtab_size = 1; > > + > > I suspect above code sniped is not needed since the size of src[0](always 1) > is > counted at the following code("strtab_size += strlen(..) + 1;"). > > > /* Compute total space required for the core symbols' strtab. */ > > - for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src) > > - if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) > > { > > - strtab_size += strlen(&info->strtab[src->st_name]) > > + 1; > > + for (ndst = i = 0; i < nsrc; i++) { > > + if (i == 0 || > > + is_core_symbol(src+i, info->sechdrs, > > info->hdr->e_shnum)) { > > src[i] rather than src+1 is better as kallsyms(); > > > + strtab_size += > > strlen(&info->strtab[src[i].st_name])+1; > > ndst++; > > } > > + } > > > > /* Append room for core symbols at end of core part. */ > > info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1); > > @@ -2312,15 +2317,15 @@ static void add_kallsyms(struct module * > > mod->core_symtab = dst = mod->module_core + info->symoffs; > > mod->core_strtab = s = mod->module_core + info->stroffs; > > src = mod->symtab; > > - *dst = *src; > > *s++ = 0; > > This "*s++"line is also not needed since the content of src[0] is copied in > the > following loop. > > If my understanding is correct, the allsym table becomes as follows by > applying this patch. > > ================== > \0\0<first core symbol>\0<second core symbol>\0... # "\0" means null > character in this case > ================== > > It should be as follows. > > ==================== > \0<first core symbol>\0<second core symbol>\0... > ==================== > > This patch would work, but need extra one byte per module. Olease let > us know if I misunderstand something. > I didn't confirm with real machine.
Please confirm with a real machine, and if the problem is there, please submit a patch to get it changed in Linus's tree, which is where this patch came from. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
