Re: [patch] Fix threaded inferiors in child after fork

Jan Kratochvil
2008-01-02T13:44:23Z

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On Wed, 02 Jan 2008 13:45:12 +0100, Daniel Jacobowitz wrote:
> On Wed, Jan 02, 2008 at 11:29:12AM +0100, Jan Kratochvil wrote:
> > + Please email any bugs, comments, and/or additions to this file to:
> > + bug-gdb@prep.ai.mit.edu */
>
> Please delete this bit from the C file and exp file; that host is
> long-gone.

Done.

> > +gdb_test "set follow-fork-mode child"
>
> Let's limit this test to GNU/Linux only; otherwise you have to figure
> out if the current target supports it.

Done.

> Otherwise this is OK. Thanks.

Committed the attached patch.

Thanks,
Jan

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2008-01-02 Jan Kratochvil <jan.kratochvil@redhat.com>

* linux-nat.c (linux_child_follow_fork): Call also CHECK_FOR_THREAD_DB.

2008-01-02 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb.threads/fork-child-threads.exp, gdb.threads/fork-child-threads.c:
New files

--- ./gdb/linux-nat.c 1 Jan 2008 22:53:11 -0000 1.71
+++ ./gdb/linux-nat.c 2 Jan 2008 12:57:23 -0000
@@ -517,6 +517,7 @@ linux_child_follow_fork (struct target_o

push_target (ops);
linux_nat_switch_fork (inferior_ptid);
+ check_for_thread_db ();

/* Reset breakpoints in the child as appropriate. */
follow_inferior_reset_breakpoints ();
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ./gdb/testsuite/gdb.threads/fork-child-threads.c 2 Jan 2008 12:57:23 -0000
@@ -0,0 +1,50 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2008 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 <http://www.gnu.org/licenses/>. */
+
+#include <pthread.h>
+#include <assert.h>
+#include <unistd.h>
+
+static void *
+start (void *arg)
+{
+ assert (0);
+ return arg;
+}
+
+int main(void)
+{
+ pthread_t thread;
+ int i;
+
+ switch (fork ())
+ {
+ case -1:
+ assert (0);
+ default:
+ break;
+ case 0:
+ i = pthread_create (&thread, NULL, start, NULL);
+ assert (i == 0);
+ i = pthread_join (thread, NULL);
+ assert (i == 0);
+
+ assert (0);
+ }
+
+ return 0;
+}
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ./gdb/testsuite/gdb.threads/fork-child-threads.exp 2 Jan 2008 12:57:23 -0000
@@ -0,0 +1,49 @@
+# Copyright (C) 2008 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 <http://www.gnu.org/licenses/>.
+
+# Only GNU/Linux is known to support `set follow-fork-mode child'.
+if { ! [istarget "*-*-linux*"] } {
+ return 0
+}
+
+set testfile fork-child-threads
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+
+gdb_load ${binfile}
+if ![runto_main] then {
+ fail "Can't run to main"
+ return 0
+}
+
+gdb_test "set follow-fork-mode child"
+gdb_breakpoint "start"
+gdb_test "continue" "Breakpoint 2, start.*" "get to the spawned thread"
+
+# Wrong:
+# * 2 LWP 4466 start (arg=0x0) at fork-child-threads.c:28
+# Correct:
+# * 3 Thread 0x40a00950 (LWP 5553) start (arg=0x0) at ../.././gdb/testsuite/gdb.threads/fork-child-threads.c:28
+# 2 Thread 0x2aaaaaac3000 (LWP 5552) 0x00000031674076dd in pthread_join (threadid=<value optimized out>, thread_return=<value optimized out>) at pthread_join.c:89
+
+gdb_test "info threads" " Thread .* Thread .*" "two threads found"