gdb/gdb-python-gil.patch

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From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Fedora GDB patches <invalid@email.com>
Date: Fri, 27 Oct 2017 21:07:50 +0200
Subject: gdb-python-gil.patch
;; Fix Python GIL with gdb.execute("continue") (Phil Muldoon, BZ 1116957).
;;=push
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -234,6 +234,14 @@ returned as a string. The default is @code{False}, in which case the
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 --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -137,6 +137,8 @@ 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 --git a/gdb/python/python.c b/gdb/python/python.c
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -545,12 +545,16 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
{
const char *arg;
PyObject *from_tty_obj = NULL, *to_string_obj = NULL;
- int from_tty, to_string;
- static const char *keywords[] = { "command", "from_tty", "to_string", NULL };
+ int from_tty, to_string, release_gil;
+ static const char *keywords[] = {"command", "from_tty", "to_string", "release_gil", NULL };
+ PyObject *release_gil_obj = NULL;
+ /* Initialize it just to avoid a GCC false warning. */
+ PyThreadState *state = NULL;
- if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|O!O!", keywords, &arg,
+ if (!gdb_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;
@@ -571,6 +575,15 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
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;
+ }
+
std::string to_string_res;
scoped_restore preventer = prevent_dont_repeat ();
@@ -593,6 +606,13 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
counted_command_line lines = read_command_lines_1 (reader, 1, nullptr);
+ /* 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();
+
{
scoped_restore save_async = make_scoped_restore (&current_ui->async,
0);
@@ -611,12 +631,24 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
execute_control_commands (lines.get (), from_tty);
}
+ /* Reacquire the GIL if it was released earlier. */
+ if (release_gil)
+ PyEval_RestoreThread (state);
+
/* Do any commands attached to breakpoint we stopped at. */
bpstat_do_actions ();
}
CATCH (except, RETURN_MASK_ALL)
{
- 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;
+ }
}
END_CATCH
diff --git a/gdb/testsuite/gdb.python/py-gil-mthread.c b/gdb/testsuite/gdb.python/py-gil-mthread.c
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-gil-mthread.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int
+main (void)
+{
+ int i;
+ for (i = 0; i < 10; i++)
+ {
+ sleep (1); /* break-here */
+ printf ("Sleeping %d\n", i);
+ }
+}
diff --git a/gdb/testsuite/gdb.python/py-gil-mthread.exp b/gdb/testsuite/gdb.python/py-gil-mthread.exp
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-gil-mthread.exp
@@ -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 $srcfile:[gdb_get_line_number "break-here"] temporary
+gdb_continue_to_breakpoint "break-here" ".* break-here .*"
+
+set test "response"
+set timeout 60
+set sleeping_last -1
+set hello_last 0
+set minimal 5
+gdb_test_multiple "python exec (open ('$srcdir/$subdir/$srcfile2').read ())" $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 --git a/gdb/testsuite/gdb.python/py-gil-mthread.py b/gdb/testsuite/gdb.python/py-gil-mthread.py
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-gil-mthread.py
@@ -0,0 +1,28 @@
+try:
+ import thread
+except:
+ 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 ( %d )" % count)
+
+# Create a threads a continue
+try:
+ thread.start_new_thread (print_thread_hello, ())
+ gdb.execute ("continue", release_gil=True)
+except:
+ try:
+ _thread.start_new_thread (print_thread_hello, ())
+ gdb.execute ("continue", release_gil=True)
+ except:
+ print ("Error: unable to start thread")
+
+while 1:
+ pass