From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32729 invoked by alias); 2 May 2014 18:06:27 -0000 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 Received: (qmail 32718 invoked by uid 89); 2 May 2014 18:06:26 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.6 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 02 May 2014 18:06:25 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s42I6O7I007092 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 2 May 2014 14:06:24 -0400 Received: from psique ([10.3.113.6]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s42I6Kkg021581 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 2 May 2014 14:06:22 -0400 From: Sergio Durigan Junior To: Pedro Alves Cc: GDB Patches Subject: Re: [PATCH 1/2] Fix PR breakpoints/16889: gdb segfaults when printing ASM SDT arguments References: <1398981131-11720-1-git-send-email-sergiodj@redhat.com> <1398981131-11720-2-git-send-email-sergiodj@redhat.com> <53636901.9090601@redhat.com> X-URL: http://www.redhat.com Date: Fri, 02 May 2014 18:06:00 -0000 In-Reply-To: (Sergio Durigan Junior's message of "Fri, 02 May 2014 13:14:29 -0300") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" X-IsSubscribed: yes X-SW-Source: 2014-05/txt/msg00020.txt.bz2 --=-=-= Content-Type: text/plain Content-length: 371 On Friday, May 02 2014, I wrote: > Here's what I am going to push by the end of the day if there are no > other comments. Pedro brought something else to my attention: the testcase messages were not unique, and I could rewrite it in order to make it more automatized. So here is the third version that I will push if there are no other comments. Thanks, -- Sergio --=-=-= Content-Type: text/x-patch Content-Disposition: inline; filename=11.patch Content-length: 6321 commit 00412478d10a782e298d9be457a1680cbb6c07c8 Author: Sergio Durigan Junior Date: Thu May 1 18:20:05 2014 -0300 Fix PR breakpoints/16889: gdb segfaults when printing ASM SDT arguments This commit fixes PR breakpoints/16889, which is about a bug that triggers when GDB tries to parse probes whose arguments do not contain the initial (and optional) "N@" part. For reference sake, the de facto format is described here: Anyway, this PR actually uncovered two bugs (related) that were happening while parsing the arguments. The first one was that the parser *was* catching *some* arguments that were missing the "N@" part, but it wasn't correctly setting the argument's type. This was causing a NULL pointer being dereferenced, ouch... The second bug uncovered was that the parser was not catching all of the cases for a probe which did not provide the "N@" part. The fix for that was to simplify the check that the code was making to identify non-prefixed probes. The code is simpler and easier to read now. I am also providing a testcase for this bug, only for x86_64 architectures. gdb/ 2014-05-01 Sergio Durigan Junior PR breakpoints/16889 * stap-probe.c (stap_parse_probe_arguments): Simplify check for non-prefixed probes (i.e., probes whose arguments do not start with "N@"). Always set the argument type to a sane value. gdb/testsuite/ 2014-05-01 Sergio Durigan Junior PR breakpoints/16889 * gdb.arch/amd64-stap-optional-prefix.S: New file. * gdb.arch/amd64-stap-optional-prefix.exp: Likewise. diff --git a/gdb/stap-probe.c b/gdb/stap-probe.c index dbe9f31..ef45495 100644 --- a/gdb/stap-probe.c +++ b/gdb/stap-probe.c @@ -1098,10 +1098,8 @@ stap_parse_probe_arguments (struct stap_probe *probe, struct gdbarch *gdbarch) Where `N' can be [+,-][4,8]. This is not mandatory, so we check it here. If we don't find it, go to the next state. */ - if ((*cur == '-' && cur[1] != '\0' && cur[2] != '@') - && cur[1] != '@') - arg.bitness = STAP_ARG_BITNESS_UNDEFINED; - else + if ((cur[0] == '-' && isdigit (cur[1]) && cur[2] == '@') + || (isdigit (cur[0]) && cur[1] == '@')) { if (*cur == '-') { @@ -1127,11 +1125,14 @@ stap_parse_probe_arguments (struct stap_probe *probe, struct gdbarch *gdbarch) } arg.bitness = b; - arg.atype = stap_get_expected_argument_type (gdbarch, b); /* Discard the number and the `@' sign. */ cur += 2; } + else + arg.bitness = STAP_ARG_BITNESS_UNDEFINED; + + arg.atype = stap_get_expected_argument_type (gdbarch, arg.bitness); expr = stap_parse_argument (&cur, arg.atype, gdbarch); diff --git a/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.S b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.S new file mode 100644 index 0000000..66689cb --- /dev/null +++ b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.S @@ -0,0 +1,32 @@ +/* Copyright (C) 2014 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include + + .file "amd64-stap-optional-prefix.S" + .text + .globl main +main: + mov %rsp,%rbp + pushq $42 + STAP_PROBE1(probe, foo, (%rsp)) + STAP_PROBE1(probe, bar, -8(%rbp)) + STAP_PROBE1(probe, foo_prefix, 8@(%rsp)) + STAP_PROBE1(probe, bar_prefix, 8@-8(%rbp)) + mov %rbp,%rsp + xor %rax,%rax + ret diff --git a/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp new file mode 100644 index 0000000..cc9d6c3 --- /dev/null +++ b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp @@ -0,0 +1,57 @@ +# Copyright 2014 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# This testcase is for PR breakpoints/16889 + +standard_testfile ".S" + +if { ![istarget "x86_64-*-*"] } { + verbose "Skipping $testfile.exp" + return +} + +if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } { + return -1 +} + +# Helper procedure to go to probe NAME + +proc goto_probe { name } { + global decimal hex + + gdb_test "break -pstap $name" "Breakpoint $decimal at $hex" + gdb_test "continue" "Breakpoint $decimal, main \\(\\) at .*\r\n.*STAP_PROBE1.*${name},.*\\)" +} + +# Helper procedure to test the probe's argument + +proc test_probe_value { value reg_val } { + gdb_test "print \$_probe_argc" "= 1" + gdb_test "print \$_probe_arg0" "= $value" + gdb_test "print \$_probe_arg0 == *((unsigned int *) (${reg_val}))" "= 1" +} + +if { ![runto_main] } { + return -1 +} + +foreach probe_name [list "foo" "bar" "foo_prefix" "bar_prefix"] \ + probe_val [list "42" "42" "42" "42"] \ + probe_reg_val [list "\$rsp" "\$rbp - 8" "\$rsp" "\$rbp - 8"] { + with_test_prefix $probe_name { + goto_probe $probe_name + test_probe_value $probe_val $probe_reg_val + } +} --=-=-=--