Fix Python GIL with gdb.execute("continue") (Phil Muldoon, BZ 1116957).

This commit is contained in:
Jan Kratochvil 2014-08-13 22:56:01 +02:00
parent 533da91091
commit 0d2fda651f
2 changed files with 231 additions and 1 deletions

223
gdb-python-gil.patch Normal file
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@ -0,0 +1,223 @@
diff -dup -ruNp gdb-7.8-orig/gdb/doc/python.texi gdb-7.8/gdb/doc/python.texi
--- gdb-7.8-orig/gdb/doc/python.texi 2014-08-13 22:04:14.162441271 +0200
+++ gdb-7.8/gdb/doc/python.texi 2014-08-13 22:07:20.894643853 +0200
@@ -228,6 +228,14 @@ returned as a string. The default is @c
return value is @code{None}. If @var{to_string} is @code{True}, the
@value{GDBN} virtual terminal will be temporarily set to unlimited width
and height, and its pagination will be disabled; @pxref{Screen Size}.
+
+The @var{release_gil} flag specifies whether @value{GDBN} ought to
+release the Python GIL before executing the command. This is useful
+in multi-threaded Python programs where by default the Python
+interpreter will acquire the GIL and lock other threads from
+executing. After the command has completed executing in @value{GDBN}
+the Python GIL is reacquired. This flag must be a boolean value. If
+omitted, it defaults to @code{False}.
@end defun
@findex gdb.breakpoints
diff -dup -ruNp gdb-7.8-orig/gdb/python/python-internal.h gdb-7.8/gdb/python/python-internal.h
--- gdb-7.8-orig/gdb/python/python-internal.h 2014-08-13 22:04:14.835441977 +0200
+++ gdb-7.8/gdb/python/python-internal.h 2014-08-13 22:07:20.895643867 +0200
@@ -143,6 +143,8 @@ typedef int Py_ssize_t;
#define PyGILState_Release(ARG) ((void)(ARG))
#define PyEval_InitThreads()
#define PyThreadState_Swap(ARG) ((void)(ARG))
+#define PyEval_SaveThread() ((void)(ARG))
+#define PyEval_RestoreThread(ARG) ((void)(ARG))
#define PyEval_ReleaseLock()
#endif
diff -dup -ruNp gdb-7.8-orig/gdb/python/python.c gdb-7.8/gdb/python/python.c
--- gdb-7.8-orig/gdb/python/python.c 2014-08-13 22:04:14.164441273 +0200
+++ gdb-7.8/gdb/python/python.c 2014-08-13 22:07:20.895643867 +0200
@@ -620,14 +620,18 @@ execute_gdb_command (PyObject *self, PyO
{
const char *arg;
PyObject *from_tty_obj = NULL, *to_string_obj = NULL;
- int from_tty, to_string;
+ PyObject *release_gil_obj = NULL;
+ int from_tty, to_string, release_gil;
volatile struct gdb_exception except;
- static char *keywords[] = {"command", "from_tty", "to_string", NULL };
+ static char *keywords[] = {"command", "from_tty", "to_string",
+ "release_gil", NULL };
char *result = NULL;
+ PyThreadState *state;
- if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!O!", keywords, &arg,
+ if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!O!O!", keywords, &arg,
&PyBool_Type, &from_tty_obj,
- &PyBool_Type, &to_string_obj))
+ &PyBool_Type, &to_string_obj,
+ &PyBool_Type, &release_gil_obj))
return NULL;
from_tty = 0;
@@ -648,12 +652,28 @@ execute_gdb_command (PyObject *self, PyO
to_string = cmp;
}
+ release_gil = 0;
+ if (release_gil_obj)
+ {
+ int cmp = PyObject_IsTrue (release_gil_obj);
+ if (cmp < 0)
+ return NULL;
+ release_gil = cmp;
+ }
+
TRY_CATCH (except, RETURN_MASK_ALL)
{
/* Copy the argument text in case the command modifies it. */
char *copy = xstrdup (arg);
struct cleanup *cleanup = make_cleanup (xfree, copy);
+ /* In the case of long running GDB commands, allow the user to
+ release the Python GIL acquired by Python. Restore the GIL
+ after the command has completed before handing back to
+ Python. */
+ if (release_gil)
+ state = PyEval_SaveThread();
+
make_cleanup_restore_integer (&interpreter_async);
interpreter_async = 0;
@@ -666,9 +686,21 @@ execute_gdb_command (PyObject *self, PyO
execute_command (copy, from_tty);
}
+ /* Reacquire the GIL if it was released earlier. */
+ if (release_gil)
+ PyEval_RestoreThread (state);
+
do_cleanups (cleanup);
}
- GDB_PY_HANDLE_EXCEPTION (except);
+ if (except.reason < 0)
+ {
+ /* Reacquire the GIL if it was released earlier. */
+ if (release_gil)
+ PyEval_RestoreThread (state);
+
+ gdbpy_convert_exception (except);
+ return NULL;
+ }
/* Do any commands attached to breakpoint we stopped at. */
bpstat_do_actions ();
diff -dup -ruNp gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.c gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.c
--- gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.c 1970-01-01 01:00:00.000000000 +0100
+++ gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.c 2014-08-13 22:33:05.052648912 +0200
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int
+main (void)
+{
+ int i;
+ for (i = 0; i < 10; i++)
+ {
+ sleep (1); /* break-here */
+ printf ("Sleeping %d\n", i);
+ }
+}
diff -dup -ruNp gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.exp gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.exp
--- gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.exp 1970-01-01 01:00:00.000000000 +0100
+++ gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.exp 2014-08-13 22:33:00.660641300 +0200
@@ -0,0 +1,69 @@
+# Copyright (C) 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 <http://www.gnu.org/licenses/>.
+
+standard_testfile .c .py
+set executable $testfile
+
+if { [prepare_for_testing $testfile.exp $executable $srcfile] } {
+ return -1
+}
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+if ![runto_main] {
+ return -1
+}
+
+gdb_breakpoint $srcfile:[gdb_get_line_number "break-here"] temporary
+gdb_continue_to_breakpoint "break-here" ".* break-here .*"
+
+set test "response"
+set timeout 60
+set sleeping_last -1
+set hello_last 0
+set minimal 5
+gdb_test_multiple "python execfile('$srcdir/$subdir/$srcfile2')" $test {
+ -re "Error: unable to start thread\r\n" {
+ fail $test
+ # Not $gdb_prompt-synced!
+ }
+ -re "Sleeping (\[0-9\]+)\r\n" {
+ set n $expect_out(1,string)
+ if { $sleeping_last + 1 != $n } {
+ fail $test
+ } else {
+ set sleeping_last $n
+ if { $sleeping_last >= $minimal && $hello_last >= $minimal } {
+ pass $test
+ } else {
+ exp_continue
+ }
+ }
+ }
+ -re "Hello \\( (\[0-9\]+) \\)\r\n" {
+ set n $expect_out(1,string)
+ if { $hello_last + 1 != $n } {
+ fail $test
+ } else {
+ set hello_last $n
+ if { $sleeping_last >= $minimal && $hello_last >= $minimal } {
+ pass $test
+ } else {
+ exp_continue
+ }
+ }
+ }
+}
diff -dup -ruNp gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.py gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.py
--- gdb-7.8-orig/gdb/testsuite/gdb.python/py-gil-mthread.py 1970-01-01 01:00:00.000000000 +0100
+++ gdb-7.8/gdb/testsuite/gdb.python/py-gil-mthread.py 2014-08-13 22:33:08.996654320 +0200
@@ -0,0 +1,22 @@
+import thread
+import time
+import gdb
+
+# Define a function for the thread
+def print_thread_hello():
+ count = 0
+ while count < 10:
+ time.sleep(1)
+ count += 1
+ print "Hello (", count, ")"
+
+# Create a threads a continue
+try:
+ thread.start_new_thread( print_thread_hello, ())
+ gdb.execute ("continue", release_gil=True)
+
+except:
+ print "Error: unable to start thread"
+
+while 1:
+ pass

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@ -26,7 +26,7 @@ Version: 7.8
# The release always contains a leading reserved number, start it at 1.
# `upstream' is not a part of `name' to stay fully rpm dependencies compatible for the testing.
Release: 16%{?dist}
Release: 17%{?dist}
License: GPLv3+ and GPLv3+ with exceptions and GPLv2+ and GPLv2+ with exceptions and GPL+ and LGPLv2+ and BSD and Public Domain and GFDL
Group: Development/Debuggers
@ -527,6 +527,9 @@ Patch925: gdb-fortran-frame-string.patch
# Fix -Werror=unused-variable error configuring babeltrace.
Patch926: gdb-babeltrace-configure.patch
# Fix Python GIL with gdb.execute("continue") (Phil Muldoon, BZ 1116957).
Patch927: gdb-python-gil.patch
%if 0%{!?rhel:1} || 0%{?rhel} > 6
# RL_STATE_FEDORA_GDB would not be found for:
# Patch642: gdb-readline62-ask-more-rh.patch
@ -811,6 +814,7 @@ find -name "*.info*"|xargs rm -f
%patch921 -p1
%patch925 -p1
%patch926 -p1
%patch927 -p1
%patch848 -p1
%if 0%{!?el6:1}
@ -1306,6 +1310,9 @@ then
fi
%changelog
* Wed Aug 13 2014 Jan Kratochvil <jan.kratochvil@redhat.com> - 7.8-17.fc21
- Fix Python GIL with gdb.execute("continue") (Phil Muldoon, BZ 1116957).
* Mon Aug 4 2014 Jan Kratochvil <jan.kratochvil@redhat.com> - 7.8-16.fc21
- Enable babeltrace compile-time feature.