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authorRusty Russell <rusty@rustcorp.com.au>2012-10-25 10:49:25 +1030
committerRusty Russell <rusty@rustcorp.com.au>2012-10-31 13:56:37 +1030
commit59ef28b1f14899b10d6b2682c7057ca00a9a3f47 (patch)
tree68ad548001fb24c0e63e1758d368a746998feb05 /kernel/module.c
parentbc909421a9c7083fcde795846d22b36a51a7be54 (diff)
downloadlinaro-lsk-59ef28b1f14899b10d6b2682c7057ca00a9a3f47.tar.gz
module: fix out-by-one error in kallsyms
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.kz@hitachi.com> Cc: stable@kernel.org
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c27
1 files changed, 16 insertions, 11 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 6085f5ef88e..6e48c3a4359 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2293,12 +2293,17 @@ static void layout_symtab(struct module *mod, struct load_info *info)
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;
+
/* 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)) {
+ 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);
@@ -2332,15 +2337,15 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
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;
- for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) {
- if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum))
- continue;
-
- dst[ndst] = *src;
- dst[ndst++].st_name = s - mod->core_strtab;
- s += strlcpy(s, &mod->strtab[src->st_name], KSYM_NAME_LEN) + 1;
+ for (ndst = i = 0; i < mod->num_symtab; i++) {
+ if (i == 0 ||
+ is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
+ dst[ndst] = src[i];
+ dst[ndst++].st_name = s - mod->core_strtab;
+ s += strlcpy(s, &mod->strtab[src[i].st_name],
+ KSYM_NAME_LEN) + 1;
+ }
}
mod->core_num_syms = ndst;
}