From a3febe3cba14b89885f42ca2f0224096a52885f6 Mon Sep 17 00:00:00 2001

From: Antoine Pitrou <antoine@python.org>

Date: Mon, 23 Apr 2018 13:19:42 +0200

Subject: [PATCH] bpo-33329: Fix multiprocessing regression on newer glibcs

Starting with glibc 2.27.9000-xxx, sigaddset() can return EINVAL for some

reserved signal numbers between 1 and NSIG.  The `range(1, NSIG)` idiom

is commonly used to select all signals for blocking with `pthread_sigmask`.

So we ignore the sigaddset() return value until we expose sigfillset()

to provide a better idiom.

---

 .../next/Library/2018-04-23-13-21-39.bpo-33329.lQ-Eod.rst  |  1 +

 Modules/signalmodule.c                                     | 14 ++++++++------

 2 files changed, 9 insertions(+), 6 deletions(-)

 create mode 100644 Misc/NEWS.d/next/Library/2018-04-23-13-21-39.bpo-33329.lQ-Eod.rst

diff --git a/Misc/NEWS.d/next/Library/2018-04-23-13-21-39.bpo-33329.lQ-Eod.rst b/Misc/NEWS.d/next/Library/2018-04-23-13-21-39.bpo-33329.lQ-Eod.rst

new file mode 100644

index 000000000000..d1a4e56d04b9

--- /dev/null

+++ b/Misc/NEWS.d/next/Library/2018-04-23-13-21-39.bpo-33329.lQ-Eod.rst

@@ -0,0 +1 @@

+Fix multiprocessing regression on newer glibcs

diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c

index 791616014384..35fd87e2d1e7 100644

--- a/Modules/signalmodule.c

+++ b/Modules/signalmodule.c

@@ -819,7 +819,6 @@ iterable_to_sigset(PyObject *iterable, sigset_t *mask)

     int result = -1;

     PyObject *iterator, *item;

     long signum;

-    int err;

     sigemptyset(mask);

@@ -841,11 +840,14 @@ iterable_to_sigset(PyObject *iterable, sigset_t *mask)

         Py_DECREF(item);

         if (signum == -1 && PyErr_Occurred())

             goto error;

-        if (0 < signum && signum < NSIG)

-            err = sigaddset(mask, (int)signum);

-        else

-            err = 1;

-        if (err) {

+        if (0 < signum && signum < NSIG) {

+            /* bpo-33329: ignore sigaddset() return value as it can fail

+             * for some reserved signals, but we want the `range(1, NSIG)`

+             * idiom to allow selecting all valid signals.

+             */

+            (void) sigaddset(mask, (int)signum);

+        }

+        else {

             PyErr_Format(PyExc_ValueError,

                          "signal number %ld out of range", signum);

             goto error;