--- /dev/null
+From 5782649ad95382dd558df97b33b64e854d8789fb Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Thu, 18 Sep 2014 22:08:58 +0100
+Subject: [PATCH] Fix bug which caused dnsmasq to become unresponsive when an
+ interface goes.
+
+---
+
+diff --git a/src/util.c b/src/util.c
+index df751c7..a729f33 100644
+--- a/src/util.c
++++ b/src/util.c
+@@ -570,18 +570,28 @@ void bump_maxfd(int fd, int *max)
+
+ int retry_send(void)
+ {
+- struct timespec waiter;
++ /* Linux kernels can return EAGAIN in perpetuity when calling
++ sendmsg() and the relevant interface has gone. Here we loop
++ retrying in EAGAIN for 1 second max, to avoid this hanging
++ dnsmasq. */
++
++ static int retries = 0;
++ struct timespec waiter;
++
+ if (errno == EAGAIN || errno == EWOULDBLOCK)
+ {
+ waiter.tv_sec = 0;
+ waiter.tv_nsec = 10000;
+ nanosleep(&waiter, NULL);
+- return 1;
++ if (retries++ < 1000)
++ return 1;
+ }
++
++ retries = 0;
+
+ if (errno == EINTR)
+ return 1;
+-
++
+ return 0;
+ }
+
+--
+1.9.1
+