[Python-checkins] cpython (merge 3.2 -> default): (Merge 3.2) Issue #11768: The signal handler of the signal module only calls

Mon Apr 18 16:30:30 CEST 2011

http://hg.python.org/cpython/rev/fdcbc8453304
changeset: 69425:fdcbc8453304
parent: 69422:fcd20a565b95
parent: 69424:28ab8c6ad8f9
user: Victor Stinner <victor.stinner at haypocalc.com>
date: Mon Apr 18 16:30:17 2011 +0200
summary:
 (Merge 3.2) Issue #11768: The signal handler of the signal module only calls
Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or
parallel calls. PyErr_SetInterrupt() writes also into the wake up file.
files:
 Lib/test/test_threadsignals.py | 8 ------
 Misc/NEWS | 4 +++
 Modules/signalmodule.c | 26 +++++++++++++--------
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/Lib/test/test_threadsignals.py b/Lib/test/test_threadsignals.py
--- a/Lib/test/test_threadsignals.py
+++ b/Lib/test/test_threadsignals.py
@@ -30,14 +30,9 @@
 
 # a function that will be spawned as a separate thread.
 def send_signals():
- print("send_signals: enter (thread %s)" % thread.get_ident(), file=sys.stderr)
- print("send_signals: raise SIGUSR1", file=sys.stderr)
 os.kill(process_pid, signal.SIGUSR1)
- print("send_signals: raise SIGUSR2", file=sys.stderr)
 os.kill(process_pid, signal.SIGUSR2)
- print("send_signals: release signalled_all", file=sys.stderr)
 signalled_all.release()
- print("send_signals: exit (thread %s)" % thread.get_ident(), file=sys.stderr)
 
 class ThreadSignals(unittest.TestCase):
 
@@ -46,12 +41,9 @@
 # We spawn a thread, have the thread send two signals, and
 # wait for it to finish. Check that we got both signals
 # and that they were run by the main thread.
- print("test_signals: acquire lock (thread %s)" % thread.get_ident(), file=sys.stderr)
 signalled_all.acquire()
 self.spawnSignallingThread()
- print("test_signals: wait lock (thread %s)" % thread.get_ident(), file=sys.stderr)
 signalled_all.acquire()
- print("test_signals: lock acquired", file=sys.stderr)
 # the signals that we asked the kernel to send
 # will come back, but we don't know when.
 # (it might even be after the thread exits
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -110,6 +110,10 @@
 Library
 -------
 
+- Issue #11768: The signal handler of the signal module only calls
+ Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or
+ parallel calls. PyErr_SetInterrupt() writes also into the wake up file.
+
 - Issue #11492: fix several issues with header folding in the email package.
 
 - Issue #11852: Add missing imports and update tests.
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -166,6 +166,20 @@
 }
 
 static void
+trip_signal(int sig_num)
+{
+ Handlers[sig_num].tripped = 1;
+ if (is_tripped)
+ return;
+ /* Set is_tripped after setting .tripped, as it gets
+ cleared in PyErr_CheckSignals() before .tripped. */
+ is_tripped = 1;
+ Py_AddPendingCall(checksignals_witharg, NULL);
+ if (wakeup_fd != -1)
+ write(wakeup_fd, "0円", 1);
+}
+
+static void
 signal_handler(int sig_num)
 {
 int save_errno = errno;
@@ -182,13 +196,7 @@
 if (getpid() == main_pid)
 #endif
 {
- Handlers[sig_num].tripped = 1;
- /* Set is_tripped after setting .tripped, as it gets
- cleared in PyErr_CheckSignals() before .tripped. */
- is_tripped = 1;
- Py_AddPendingCall(checksignals_witharg, NULL);
- if (wakeup_fd != -1)
- write(wakeup_fd, "0円", 1);
+ trip_signal(sig_num);
 }
 
 #ifndef HAVE_SIGACTION
@@ -946,9 +954,7 @@
 void
 PyErr_SetInterrupt(void)
 {
- is_tripped = 1;
- Handlers[SIGINT].tripped = 1;
- Py_AddPendingCall((int (*)(void *))PyErr_CheckSignals, NULL);
+ trip_signal(SIGINT);
 }
 
 void
-- 
Repository URL: http://hg.python.org/cpython
