From patchwork Wed Oct 28 23:18:27 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 9441 Received: (qmail 17682 invoked by alias); 28 Oct 2015 23:18:31 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 17668 invoked by uid 89); 28 Oct 2015 23:18:31 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-ob0-f175.google.com MIME-Version: 1.0 X-Received: by 10.60.67.1 with SMTP id j1mr36406562oet.61.1446074308051; Wed, 28 Oct 2015 16:18:28 -0700 (PDT) In-Reply-To: References: <20151028114906.GA7686@gmail.com> Date: Wed, 28 Oct 2015 16:18:27 -0700 Message-ID: Subject: Re: [PATCH] [BZ #19178] ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA conflict From: "H.J. Lu" To: GNU C Library , mark.hatle@windriver.com On Wed, Oct 28, 2015 at 3:04 PM, H.J. Lu wrote: > On Wed, Oct 28, 2015 at 6:42 AM, H.J. Lu wrote: >> On Wed, Oct 28, 2015 at 4:49 AM, H.J. Lu wrote: >>> _dl_debug_bindings updates relocation type class with 4 and 8. But >>> ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA may be defined to 4. This patch >>> adds ELF_RTYPE_CLASS_TLS/ELF_RTYPE_CLASS_IFUNC and use them in >>> _dl_debug_bindings. >>> >>> Tested on i686 and x86-64. OK for master and 2.22 branch? >>> >>> >>> H.J. >>> -- >>> [BZ #19178] >>> * dl-lookup.c (_dl_debug_bindings): Replace 4 and 8 with >>> ELF_RTYPE_CLASS_TLS and ELF_RTYPE_CLASS_IFUNC. >>> * sysdeps/generic/ldsodefs.h (ELF_RTYPE_CLASS_TLS): New. >>> (ELF_RTYPE_CLASS_IFUNC): Likewise. >> >> >> It doesn't work with prelink. >> > > Here is the correct patch. Verified with prelink. OK for master > and 2.22 branch? Here is the updated patch to keep only ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY bits for prelink. Mark, can you verify it with prelink? Thanks. Tested-by: Mark Hatle From 7f16bc353495e6c2ec101abeee4ba26525e6c725 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 28 Oct 2015 07:49:44 -0700 Subject: [PATCH] Keep only ELF_RTYPE_CLASS_{PLT|COPY} bits for prelink prelink runs ld.so with the environment variable LD_TRACE_PRELINKING set to dump the relocation type class from _dl_debug_bindings. prelink has the following relocation type classes: #define RTYPE_CLASS_VALID 8 #define RTYPE_CLASS_PLT (8|1) #define RTYPE_CLASS_COPY (8|2) #define RTYPE_CLASS_TLS (8|4) where ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA has a conflict with RTYPE_CLASS_TLS. Since prelink only uses ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY bits, we should clear the other bits when the DL_DEBUG_PRELINK bit is set. [BZ #19178] * elf/dl-lookup.c (RTYPE_CLASS_VALID): New. (RTYPE_CLASS_PLT): Likewise. (RTYPE_CLASS_COPY): Likewise. (RTYPE_CLASS_TLS): Likewise. (_dl_debug_bindings): Use RTYPE_CLASS_TLS and RTYPE_CLASS_VALID to set relocation type class for DL_DEBUG_PRELINK. Keep only ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY bits for DL_DEBUG_PRELINK. --- elf/dl-lookup.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 581fb20..6ae6cc3 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -1016,6 +1016,18 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, #ifdef SHARED if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK) { +/* ELF_RTYPE_CLASS_XXX must match RTYPE_CLASS_XXX used by prelink with + LD_TRACE_PRELINKING. */ +#define RTYPE_CLASS_VALID 8 +#define RTYPE_CLASS_PLT (8|1) +#define RTYPE_CLASS_COPY (8|2) +#define RTYPE_CLASS_TLS (8|4) +#if ELF_RTYPE_CLASS_PLT != 0 && ELF_RTYPE_CLASS_PLT != 1 +# error ELF_RTYPE_CLASS_PLT must be 0 or 1! +#endif +#if ELF_RTYPE_CLASS_COPY != 0 && ELF_RTYPE_CLASS_COPY != 2 +# error ELF_RTYPE_CLASS_COPY must be 0 or 2! +#endif int conflict = 0; struct sym_val val = { NULL, NULL }; @@ -1071,12 +1083,17 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, if (value->s) { + /* Keep only ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY + bits since since prelink only uses them. */ + type_class &= ELF_RTYPE_CLASS_PLT | ELF_RTYPE_CLASS_COPY; if (__glibc_unlikely (ELFW(ST_TYPE) (value->s->st_info) == STT_TLS)) - type_class = 4; + /* Clear the RTYPE_CLASS_VALID bit in RTYPE_CLASS_TLS. */ + type_class = RTYPE_CLASS_TLS & ~RTYPE_CLASS_VALID; else if (__glibc_unlikely (ELFW(ST_TYPE) (value->s->st_info) == STT_GNU_IFUNC)) - type_class |= 8; + /* Set the RTYPE_CLASS_VALID bit. */ + type_class |= RTYPE_CLASS_VALID; } if (conflict -- 2.4.3