diff --git a/SOURCES/make-4.2.1-nonblocking-reads.patch b/SOURCES/make-4.2.1-nonblocking-reads.patch
new file mode 100644
index 0000000..76b9545
--- /dev/null
+++ b/SOURCES/make-4.2.1-nonblocking-reads.patch
@@ -0,0 +1,164 @@
+From b552b05251980f693c729e251f93f5225b400714 Mon Sep 17 00:00:00 2001
+From: Paul Smith <psmith@gnu.org>
+Date: Sat, 3 Jun 2017 16:20:51 -0400
+Subject: [SV 51159] Use a non-blocking read with pselect to avoid hangs.
+
+* posixos.c (set_blocking): Set blocking on a file descriptor.
+(jobserver_setup): Set non-blocking on the jobserver read side.
+(jobserver_parse_auth): Ditto.
+(jobserver_acquire_all): Set blocking to avoid a busy-wait loop.
+(jobserver_acquire): If the non-blocking read() returns without
+taking a token then try again.
+
+diff --git a/posixos.c b/posixos.c
+index e642d7f..dbafa51 100644
+--- a/posixos.c
++++ b/posixos.c
+@@ -62,6 +62,24 @@ make_job_rfd (void)
+ #endif
+ }
+
++static void
++set_blocking (int fd, int blocking)
++{
++ // If we're not using pselect() don't change the blocking
++#ifdef HAVE_PSELECT
++ int flags;
++ EINTRLOOP (flags, fcntl (fd, F_GETFL));
++ if (flags >= 0)
++ {
++ int r;
++ flags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
++ EINTRLOOP (r, fcntl (fd, F_SETFL, flags));
++ if (r < 0)
++ pfatal_with_name ("fcntl(O_NONBLOCK)");
++ }
++#endif
++}
++
+ unsigned int
+ jobserver_setup (int slots)
+ {
+@@ -86,6 +104,9 @@ jobserver_setup (int slots)
+ pfatal_with_name (_("init jobserver pipe"));
+ }
+
++ /* When using pselect() we want the read to be non-blocking. */
++ set_blocking (job_fds[0], 0);
++
+ return 1;
+ }
+
+@@ -121,6 +142,9 @@ jobserver_parse_auth (const char *auth)
+ return 0;
+ }
+
++ /* When using pselect() we want the read to be non-blocking. */
++ set_blocking (job_fds[0], 0);
++
+ return 1;
+ }
+
+@@ -169,7 +193,10 @@ jobserver_acquire_all (void)
+ {
+ unsigned int tokens = 0;
+
+- /* Close the write side, so the read() won't hang. */
++ /* Use blocking reads to wait for all outstanding jobs. */
++ set_blocking (job_fds[0], 1);
++
++ /* Close the write side, so the read() won't hang forever. */
+ close (job_fds[1]);
+ job_fds[1] = -1;
+
+@@ -236,18 +263,12 @@ jobserver_pre_acquire (void)
+ unsigned int
+ jobserver_acquire (int timeout)
+ {
+- sigset_t empty;
+- fd_set readfds;
+ struct timespec spec;
+ struct timespec *specp = NULL;
+- int r;
+- char intake;
++ sigset_t empty;
+
+ sigemptyset (&empty);
+
+- FD_ZERO (&readfds);
+- FD_SET (job_fds[0], &readfds);
+-
+ if (timeout)
+ {
+ /* Alarm after one second (is this too granular?) */
+@@ -256,28 +277,52 @@ jobserver_acquire (int timeout)
+ specp = &spec;
+ }
+
+- r = pselect (job_fds[0]+1, &readfds, NULL, NULL, specp, &empty);
+-
+- if (r == -1)
++ while (1)
+ {
+- /* Better be SIGCHLD. */
+- if (errno != EINTR)
+- pfatal_with_name (_("pselect jobs pipe"));
+- return 0;
+- }
++ fd_set readfds;
++ int r;
++ char intake;
+
+- if (r == 0)
+- /* Timeout. */
+- return 0;
++ FD_ZERO (&readfds);
++ FD_SET (job_fds[0], &readfds);
+
+- /* The read FD is ready: read it! */
+- EINTRLOOP (r, read (job_fds[0], &intake, 1));
+- if (r < 0)
+- pfatal_with_name (_("read jobs pipe"));
++ r = pselect (job_fds[0]+1, &readfds, NULL, NULL, specp, &empty);
++ if (r < 0)
++ switch (errno)
++ {
++ case EINTR:
++ /* SIGCHLD will show up as an EINTR. */
++ return 0;
++
++ case EBADF:
++ /* Someone closed the jobs pipe.
++ That shouldn't happen but if it does we're done. */
++ O (fatal, NILF, _("job server shut down"));
+
+- /* What does it mean if read() returns 0? It shouldn't happen because only
+- the master make can reap all the tokens and close the write side...?? */
+- return r > 0;
++ default:
++ pfatal_with_name (_("pselect jobs pipe"));
++ }
++
++ if (r == 0)
++ /* Timeout. */
++ return 0;
++
++ /* The read FD is ready: read it! This is non-blocking. */
++ EINTRLOOP (r, read (job_fds[0], &intake, 1));
++
++ if (r < 0)
++ {
++ /* Someone sniped our token! Try again. */
++ if (errno == EAGAIN)
++ continue;
++
++ pfatal_with_name (_("read jobs pipe"));
++ }
++
++ /* read() should never return 0: only the master make can reap all the
++ tokens and close the write side...?? */
++ return r > 0;
++ }
+ }
+
+ #else
diff --git a/SPECS/make.spec b/SPECS/make.spec
index 9c78cae..93cfa40 100644
--- a/SPECS/make.spec
+++ b/SPECS/make.spec
@@ -4,7 +4,7 @@ Summary: A GNU tool which simplifies the build process for users
Name: %{?scl_prefix}make
Epoch: 1
Version: 4.2.1
-Release: 4%{?dist}
+Release: 4%{?dist}.0.1
License: GPLv2+
Group: Development/Tools
URL: http://www.gnu.org/software/make/
@@ -25,6 +25,10 @@ Patch6: make-4.2-warn_undefined_function.patch
# http://lists.gnu.org/archive/html/bug-make/2011-06/msg00032.html
Patch7: make-4.2-trace.patch
+# Upstream patch: https://git.savannah.gnu.org/cgit/make.git/commit/?id=b552b05251980f693c729e251f93f5225b400714
+# Avoids hangs in parallel builds
+Patch8: make-4.2.1-nonblocking-reads.patch
+
# Buildroot: %(mktemp -ud %{_tmppath}/make-%{version}-%{release}-XXXXXX)
BuildRoot: %{_tmppath}/make-%{version}-%{release}-root-%(%{__id_u} -n)
Requires(post): /sbin/install-info
@@ -51,6 +55,7 @@ echo "STARTING PREP of make"
%patch5 -p1
%patch6 -p1
%patch7 -p1
+%patch8 -p1
rm -f tests/scripts/features/parallelism.orig