diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 963df8a..f6217c3 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1437,6 +1437,12 @@
 {
 #ifdef HAVE_SIGACTION
 	struct sigaction context;
+	/* Initialize context.sa_handler to SIG_ERR which makes about as
+	 * much sense as anything else.  It should get overwritten if
+	 * sigaction actually succeeds and otherwise we avoid an
+	 * uninitialized memory read.
+	 */
+	context.sa_handler = SIG_ERR;
 	sigaction(sig, NULL, &context);
 	return context.sa_handler;
 #else
@@ -1453,6 +1459,12 @@
 #ifdef HAVE_SIGACTION
 	struct sigaction context;
 	PyOS_sighandler_t oldhandler;
+	/* Initialize context.sa_handler to SIG_ERR which makes about as
+	 * much sense as anything else.  It should get overwritten if
+	 * sigaction actually succeeds and otherwise we avoid an
+	 * uninitialized memory read.
+	 */
+	context.sa_handler = SIG_ERR;
 	sigaction(sig, NULL, &context);
 	oldhandler = context.sa_handler;
 	context.sa_handler = handler;