From patchwork Tue Feb 9 19:12:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Seitz X-Patchwork-Id: 10777 Received: (qmail 86757 invoked by alias); 9 Feb 2016 19:12:30 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 86747 invoked by uid 89); 9 Feb 2016 19:12:29 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=BAYES_00, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=execlp, whenever, non-null, debugger 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 (AES256-GCM-SHA384 encrypted) ESMTPS; Tue, 09 Feb 2016 19:12:27 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 9AE3E3C88C6 for ; Tue, 9 Feb 2016 19:12:26 +0000 (UTC) Received: from valrhona.uglyboxes.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u19JCQnC021169 for ; Tue, 9 Feb 2016 14:12:26 -0500 From: Keith Seitz To: gdb-patches@sourceware.org Subject: [PATCH] breakpoints/19546: Fix crash after updating breakpoints Date: Tue, 9 Feb 2016 11:12:25 -0800 Message-Id: <1455045145-6101-1-git-send-email-keiths@redhat.com> X-IsSubscribed: yes One of the last checks update_breakpoints_after_exec does while looping over the list of breakpoints is check that the breakpoint has a valid location spec. It uses event_location_empty_p to check if the location spec is "empty", and if it is, the breakpoint is deleted. momentary_breakpoint types rely on setting the breakpoint structure's location spec to NULL, thereby causing an update to delete the breakpoint. However, event_location_empty_p assumed that locations were never NULL. As a result, GDB would crash dereferencing a NULL pointer whenever update_breakpoints_after_exec would encounter a momentary_breakpoint. This patch creates a new wrapper/helper function which tests that the given breakpoint's location spec is non-NULL and if it is not "empty" or "unspecified." gdb/ChangeLog PR breakpoints/19546 * breakpoint.c (breakpoint_event_location_empty_p): New function. (update_breakpoints_after_exec, bkpt_re_set): Use this new function instead of event_location_empty_p. gdb/testsuite/ChangeLog PR breakpoints/19546 * gdb.base/inf-exec.c: New file. * gdb.base/inf-exec2.c: New file. * gdb.base/inf-exec.exp: New file. diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index c059861..f99a7ab 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -3764,6 +3764,14 @@ create_exception_master_breakpoint (void) } } +/* Does B have a location spec? */ + +static int +breakpoint_event_location_empty_p (const struct breakpoint *b) +{ + return b->location != NULL && event_location_empty_p (b->location); +} + void update_breakpoints_after_exec (void) { @@ -3878,7 +3886,7 @@ update_breakpoints_after_exec (void) /* Without a symbolic address, we have little hope of the pre-exec() address meaning the same thing in the post-exec() a.out. */ - if (event_location_empty_p (b->location)) + if (breakpoint_event_location_empty_p (b)) { delete_breakpoint (b); continue; @@ -13063,7 +13071,7 @@ static void bkpt_re_set (struct breakpoint *b) { /* FIXME: is this still reachable? */ - if (event_location_empty_p (b->location)) + if (breakpoint_event_location_empty_p (b)) { /* Anything without a location can't be re-set. */ delete_breakpoint (b); diff --git a/gdb/testsuite/gdb.base/inf-exec.c b/gdb/testsuite/gdb.base/inf-exec.c new file mode 100644 index 0000000..6617934 --- /dev/null +++ b/gdb/testsuite/gdb.base/inf-exec.c @@ -0,0 +1,28 @@ +/* This test program is part of GDB, the GNU debugger. + + Copyright 2016 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 . */ + +#include + +int +main (int argc, char ** argv) +{ + const char *prog = "inf-exec2"; + + execlp (prog, prog, (char *) 0); + + return 0; +} diff --git a/gdb/testsuite/gdb.base/inf-exec.exp b/gdb/testsuite/gdb.base/inf-exec.exp new file mode 100644 index 0000000..79cb413 --- /dev/null +++ b/gdb/testsuite/gdb.base/inf-exec.exp @@ -0,0 +1,49 @@ +# Copyright 2016 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 . + +# Test an inferior function call which execs a new program. +# This is a test for breakpoints/19546. + +standard_testfile inf-exec.c + +set testfile2 "inf-exec2" +set srcfile2 "${testfile2}.c" +set binfile2 [standard_output_file $testfile2] + +# Build the two executables for the test. +if {[gdb_compile $srcdir/$subdir/$srcfile $binfile executable debug] != ""} { + untested "could not build $binfile" + return -1 +} +if {[gdb_compile $srcdir/$subdir/$srcfile2 $binfile2 executable debug] != ""} { + untested "could not build $binfile2" + return -1 +} + +gdb_exit +clean_restart $binfile + +if {![runto_main]} { + untested "could not run to main" + return -1 +} + +set expected_result "process \[0-9\]+ is executing new program: $binfile2" +append expected_result "\[\r\n\]+" +append expected_result "Breakpoint 1, main.*at .*/$srcfile2:\[0-9\]+" +append expected_result ".*" + +gdb_test "call execlp \(\"$binfile2\", \"$binfile2\", \(char \*\)0\)" \ + $expected_result "call execlp" diff --git a/gdb/testsuite/gdb.base/inf-exec2.c b/gdb/testsuite/gdb.base/inf-exec2.c new file mode 100644 index 0000000..bb2a008 --- /dev/null +++ b/gdb/testsuite/gdb.base/inf-exec2.c @@ -0,0 +1,22 @@ +/* This test program is part of GDB, the GNU debugger. + + Copyright 2016 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 . */ + +int +main (int argc, char ** argv) +{ + return 0; +}