cpython: fdcbc8453304 (original) (raw)

Mercurial > cpython

changeset 69425:fdcbc8453304

(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. [#11768]

Victor Stinner victor.stinner@haypocalc.com
date	Mon, 18 Apr 2011 16:30:17 +0200
parents	fcd20a565b95(current diff)28ab8c6ad8f9(diff)
children	2f3fda9d3906
files	Lib/test/test_threadsignals.py Misc/NEWS
diffstat	3 files changed, 20 insertions(+), 18 deletions(-)[+] [-] Lib/test/test_threadsignals.py 8 Misc/NEWS 4 Modules/signalmodule.c 26

line wrap: on

line diff

--- a/Lib/test/test_threadsignals.py +++ b/Lib/test/test_threadsignals.py @@ -30,14 +30,9 @@ def handle_signals(sig,frame):

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 @@ class ThreadSignals(unittest.TestCase): # 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)[](#l1.22)
   signalled_all.acquire()[](#l1.23)
   self.spawnSignallingThread()[](#l1.24)

   print("test_signals: wait lock (thread %s)" % thread.get_ident(), file=sys.stderr)[](#l1.25)
   signalled_all.acquire()[](#l1.26)

   print("test_signals: lock acquired", file=sys.stderr)[](#l1.27)
   # the signals that we asked the kernel to send[](#l1.28)
   # will come back, but we don't know when.[](#l1.29)
   # (it might even be after the thread exits[](#l1.30)

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -110,6 +110,10 @@ Core and Builtins 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.

--- a/Modules/signalmodule.c +++ b/Modules/signalmodule.c @@ -166,6 +166,20 @@ checksignals_witharg(void * unused) } static void +trip_signal(int sig_num) +{

Handlers[sig_num].tripped = 1;
if (is_tripped)
```
   return;[](#l3.11)
```
/* Set is_tripped after setting .tripped, as it gets

  cleared in PyErr_CheckSignals() before .tripped. */[](#l3.13)

is_tripped = 1;
Py_AddPendingCall(checksignals_witharg, NULL);
if (wakeup_fd != -1)
```
   write(wakeup_fd, "\0", 1);[](#l3.17)
```

+} + +static void signal_handler(int sig_num) { int save_errno = errno; @@ -182,13 +196,7 @@ signal_handler(int sig_num) if (getpid() == main_pid) #endif {

   Handlers[sig_num].tripped = 1;[](#l3.28)

   /* Set is_tripped after setting .tripped, as it gets[](#l3.29)

      cleared in PyErr_CheckSignals() before .tripped. */[](#l3.30)

```
   is_tripped = 1;[](#l3.31)
```

   Py_AddPendingCall(checksignals_witharg, NULL);[](#l3.32)

```
   if (wakeup_fd != -1)[](#l3.33)
```

       write(wakeup_fd, "\0", 1);[](#l3.34)

```
   trip_signal(sig_num);[](#l3.35)
```
}

#ifndef HAVE_SIGACTION @@ -946,9 +954,7 @@ PyErr_CheckSignals(void) void PyErr_SetInterrupt(void) {

is_tripped = 1;
Handlers[SIGINT].tripped = 1;
Py_AddPendingCall((int (*)(void *))PyErr_CheckSignals, NULL);

trip_signal(SIGINT);

} void