From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30192 invoked by alias); 18 Mar 2009 04:36:39 -0000 Received: (qmail 30115 invoked by uid 22791); 18 Mar 2009 04:36:37 -0000 X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00,J_CHICKENPOX_41,J_CHICKENPOX_63,SPF_PASS X-Spam-Check-By: sourceware.org Received: from smtp-out.google.com (HELO smtp-out.google.com) (216.239.33.17) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 18 Mar 2009 04:36:32 +0000 Received: from wpaz29.hot.corp.google.com (wpaz29.hot.corp.google.com [172.24.198.93]) by smtp-out.google.com with ESMTP id n2I4aTSY018252 for ; Wed, 18 Mar 2009 04:36:29 GMT Received: from localhost (ruffy.mtv.corp.google.com [172.18.118.116]) by wpaz29.hot.corp.google.com with ESMTP id n2I4aRIW024709; Tue, 17 Mar 2009 21:36:27 -0700 Received: by localhost (Postfix, from userid 67641) id D9F121C7301; Tue, 17 Mar 2009 21:36:26 -0700 (PDT) To: ppluzhnikov@google.com, gdb-patches@sourceware.org Subject: [RFA] (display_uses_solib_p): Redo loop, scan element list backwards. Message-Id: <20090318043626.D9F121C7301@localhost> Date: Wed, 18 Mar 2009 04:49:00 -0000 From: dje@google.com (Doug Evans) X-System-Of-Record: true X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2009-03/txt/msg00363.txt.bz2 Hi. I noticed sigbpt.exp is failing. I was getting a "Value out of range" error inside display_uses_solib_p. I traced it to the expression elements array being referenced out of bounds. I think this patch is the right fix. The expression elements array needs to be scanned backwards when using operator_length: it examines the element at the _end_ of the array. Ok to check in? 2009-03-17 Doug Evans * printcmd.c (display_uses_solib_p): Redo loop, scan element list backwards. Index: printcmd.c =================================================================== RCS file: /cvs/src/src/gdb/printcmd.c,v retrieving revision 1.147 diff -u -p -r1.147 printcmd.c --- printcmd.c 9 Mar 2009 22:38:37 -0000 1.147 +++ printcmd.c 18 Mar 2009 04:28:26 -0000 @@ -1763,18 +1763,23 @@ static int display_uses_solib_p (const struct display *d, const struct so_list *solib) { - int i; + int endpos; struct expression *const exp = d->exp; + union exp_element *const elts = exp->elts; if (d->block != NULL && solib_contains_address_p (solib, d->block->startaddr)) return 1; - for (i = 0; i < exp->nelts; ) + for (endpos = exp->nelts; endpos > 0; ) { - int args, oplen = 0; - const union exp_element *const elts = exp->elts; + int i, args, oplen = 0; + exp->language_defn->la_exp_desc->operator_length (exp, endpos, + &oplen, &args); + gdb_assert (oplen > 0); + + i = endpos - oplen; if (elts[i].opcode == OP_VAR_VALUE) { const struct block *const block = elts[i + 1].block; @@ -1789,11 +1794,9 @@ display_uses_solib_p (const struct displ if (section && section->objfile == solib->objfile) return 1; } - exp->language_defn->la_exp_desc->operator_length (exp, i + 1, - &oplen, &args); - gdb_assert (oplen > 0); - i += oplen; + endpos -= oplen; } + return 0; }