From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11768 invoked by alias); 1 May 2014 21:52:23 -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 11618 invoked by uid 89); 1 May 2014 21:52:22 -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; Thu, 01 May 2014 21:52:21 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s41LqJCK004679 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 1 May 2014 17:52:20 -0400 Received: from psique.redhat.com ([10.3.113.6]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s41LqH2R001411; Thu, 1 May 2014 17:52:19 -0400 From: Sergio Durigan Junior To: GDB Patches Cc: Sergio Durigan Junior Subject: [PATCH 1/2] Fix PR breakpoints/16889: gdb segfaults when printing ASM SDT arguments Date: Thu, 01 May 2014 21:52:00 -0000 Message-Id: <1398981131-11720-2-git-send-email-sergiodj@redhat.com> In-Reply-To: <1398981131-11720-1-git-send-email-sergiodj@redhat.com> References: <1398981131-11720-1-git-send-email-sergiodj@redhat.com> X-IsSubscribed: yes X-SW-Source: 2014-05/txt/msg00010.txt.bz2 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/testsuite/gdb.arch/amd64-stap-optional-prefix.S: New file. * gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp: Likewise. --- gdb/stap-probe.c | 11 ++--- .../gdb.arch/amd64-stap-optional-prefix.S | 29 +++++++++++++ .../gdb.arch/amd64-stap-optional-prefix.exp | 50 ++++++++++++++++++++++ 3 files changed, 85 insertions(+), 5 deletions(-) create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.S create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp 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..9c86f2d --- /dev/null +++ b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.S @@ -0,0 +1,29 @@ +/* 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)) + 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..9747dc8 --- /dev/null +++ b/gdb/testsuite/gdb.arch/amd64-stap-optional-prefix.exp @@ -0,0 +1,50 @@ +# 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 + +if { ![istarget "x86_64-*-*"] } { + verbose "Skipping amd64-stap-special-operands.exp" + return +} + +standard_testfile ".S" + +if { [prepare_for_testing $testfile.exp $testfile $srcfile] } { + untested amd64-stap-optional-prefix.exp + return -1 +} + +# Run to the first probe (foo). + +if { ![runto "-pstap foo"] } { + fail "run to probe foo" + return +} + +# Probe foo's first argument must me == $rsp + +gdb_test "print \$_probe_argc" "= 1" +gdb_test "print \$_probe_arg0" "= 42" +gdb_test "print \$_probe_arg0 == *((unsigned int *) \$rsp)" "= 1" + +# Continuing to the second probe (bar) + +gdb_test "break -pstap bar" "Breakpoint $decimal at $hex" +gdb_test "continue" "Breakpoint $decimal, main \\(\\) at .*\r\n.*STAP_PROBE1.*bar,.*\\)" + +gdb_test "print \$_probe_argc" "= 1" +gdb_test "print \$_probe_arg0" "= 42" +gdb_test "print \$_probe_arg0 == *((unsigned int *) (\$rbp - 8))" "= 1" -- 1.7.11.7