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authorUlrich Drepper <drepper@redhat.com>2009-12-15 12:32:27 -0800
committerUlrich Drepper <drepper@redhat.com>2009-12-15 12:32:27 -0800
commit2af6396817fb9df98e63de75dd59fd999ee9f1d0 (patch)
treed66827c66d770f1f3d697dbb027b59064e6ab0e0 /elf/dl-lookup.c
parent2510d01ddba195f8cfaa3c2349f75e0612719d82 (diff)
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Avoid ELF lookup race.
On some architectures the update of the l_used field in the lookup functions races with setting the other bits in the bitfield. Simply avoid this and optimize use of l_used in general.
Diffstat (limited to 'elf/dl-lookup.c')
-rw-r--r--elf/dl-lookup.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index c1a1366d6f..763ec16fa4 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -777,7 +777,7 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
if (__builtin_expect (protected != 0, 0))
{
/* It is very tricky. We need to figure out what value to
- return for the protected symbol. */
+ return for the protected symbol. */
if (type_class == ELF_RTYPE_CLASS_PLT)
{
if (current_value.s != NULL && current_value.m != undef_map)
@@ -822,7 +822,8 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
version, type_class, flags, skip_map);
/* The object is used. */
- current_value.m->l_used = 1;
+ if (__builtin_expect (current_value.m->l_used == 0, 0))
+ current_value.m->l_used = 1;
if (__builtin_expect (GLRO(dl_debug_mask)
& (DL_DEBUG_BINDINGS|DL_DEBUG_PRELINK), 0))
@@ -844,7 +845,7 @@ _dl_setup_hash (struct link_map *map)
Elf_Symndx nchain;
if (__builtin_expect (map->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
- + DT_THISPROCNUM + DT_VERSIONTAGNUM
+ + DT_THISPROCNUM + DT_VERSIONTAGNUM
+ DT_EXTRANUM + DT_VALNUM] != NULL, 1))
{
Elf32_Word *hash32