diff options
Diffstat (limited to 'meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch')
| -rw-r--r-- | meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch new file mode 100644 index 0000000000..ad0a1147aa --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch @@ -0,0 +1,124 @@ +From ddcacd91cc10ff92d6201eda87047d029c14158d Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Thu, 11 Feb 2021 11:40:11 +0000 +Subject: [PATCH] i386: Avoid lazy relocation of tlsdesc [BZ #27137] + +Lazy tlsdesc relocation is racy because the static tls optimization and +tlsdesc management operations are done without holding the dlopen lock. + +This similar to the commit b7cf203b5c17dd6d9878537d41e0c7cc3d270a67 +for aarch64, but it fixes a different race: bug 27137. + +On i386 the code is a bit more complicated than on x86_64 because both +rel and rela relocs are supported. +--- + sysdeps/i386/dl-machine.h | 76 ++++++++++++++++++--------------------- + 1 file changed, 34 insertions(+), 42 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=ddcacd91cc10ff92d6201eda87047d029c14158d] +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h +index 23e9cc3bfb..590b41d8d7 100644 +--- a/sysdeps/i386/dl-machine.h ++++ b/sysdeps/i386/dl-machine.h +@@ -688,50 +688,32 @@ elf_machine_lazy_rel (struct link_map *map, + } + else if (__glibc_likely (r_type == R_386_TLS_DESC)) + { +- struct tlsdesc volatile * __attribute__((__unused__)) td = +- (struct tlsdesc volatile *)reloc_addr; +- +- /* Handle relocations that reference the local *ABS* in a simple +- way, so as to preserve a potential addend. */ +- if (ELF32_R_SYM (reloc->r_info) == 0) +- td->entry = _dl_tlsdesc_resolve_abs_plus_addend; +- /* Given a known-zero addend, we can store a pointer to the +- reloc in the arg position. */ +- else if (td->arg == 0) +- { +- td->arg = (void*)reloc; +- td->entry = _dl_tlsdesc_resolve_rel; +- } +- else +- { +- /* We could handle non-*ABS* relocations with non-zero addends +- by allocating dynamically an arg to hold a pointer to the +- reloc, but that sounds pointless. */ +- const Elf32_Rel *const r = reloc; +- /* The code below was borrowed from elf_dynamic_do_rel(). */ +- const ElfW(Sym) *const symtab = +- (const void *) D_PTR (map, l_info[DT_SYMTAB]); ++ const Elf32_Rel *const r = reloc; ++ /* The code below was borrowed from elf_dynamic_do_rel(). */ ++ const ElfW(Sym) *const symtab = ++ (const void *) D_PTR (map, l_info[DT_SYMTAB]); + ++ /* Always initialize TLS descriptors completely at load time, in ++ case static TLS is allocated for it that requires locking. */ + # ifdef RTLD_BOOTSTRAP +- /* The dynamic linker always uses versioning. */ +- assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); ++ /* The dynamic linker always uses versioning. */ ++ assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); + # else +- if (map->l_info[VERSYMIDX (DT_VERSYM)]) ++ if (map->l_info[VERSYMIDX (DT_VERSYM)]) + # endif +- { +- const ElfW(Half) *const version = +- (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); +- ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], +- &map->l_versions[ndx], +- (void *) (l_addr + r->r_offset), skip_ifunc); +- } ++ { ++ const ElfW(Half) *const version = ++ (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); ++ ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], ++ &map->l_versions[ndx], ++ (void *) (l_addr + r->r_offset), skip_ifunc); ++ } + # ifndef RTLD_BOOTSTRAP +- else +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, +- (void *) (l_addr + r->r_offset), skip_ifunc); ++ else ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, ++ (void *) (l_addr + r->r_offset), skip_ifunc); + # endif +- } + } + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) + { +@@ -758,11 +740,21 @@ elf_machine_lazy_rela (struct link_map *map, + ; + else if (__glibc_likely (r_type == R_386_TLS_DESC)) + { +- struct tlsdesc volatile * __attribute__((__unused__)) td = +- (struct tlsdesc volatile *)reloc_addr; ++ const Elf_Symndx symndx = ELFW (R_SYM) (reloc->r_info); ++ const ElfW (Sym) *symtab = (const void *)D_PTR (map, l_info[DT_SYMTAB]); ++ const ElfW (Sym) *sym = &symtab[symndx]; ++ const struct r_found_version *version = NULL; ++ ++ if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL) ++ { ++ const ElfW (Half) *vernum = ++ (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); ++ version = &map->l_versions[vernum[symndx] & 0x7fff]; ++ } + +- td->arg = (void*)reloc; +- td->entry = _dl_tlsdesc_resolve_rela; ++ /* Always initialize TLS descriptors completely at load time, in ++ case static TLS is allocated for it that requires locking. */ ++ elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc); + } + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) + { +-- +2.27.0 |