diff --git a/src/Flare.cc b/src/Flare.cc
index 960e66cbf4..dcb5fa2c1f 100644
--- a/src/Flare.cc
+++ b/src/Flare.cc
@@ -1,6 +1,7 @@
 // See the file "COPYING" in the main distribution directory for copyright.
 
 #include "Flare.h"
+#include "Reporter.h"
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
@@ -12,6 +13,13 @@ Flare::Flare()
 	{
 	}
 
+static void bad_pipe_op(const char* which)
+	{
+	char buf[256];
+	strerror_r(errno, buf, sizeof(buf));
+	reporter->FatalErrorWithCore("unexpected pipe %s failure: %s", which, buf);
+	}
+
 void Flare::Fire()
 	{
 	char tmp;
@@ -24,11 +32,20 @@ void Flare::Fire()
 			// Success -- wrote a byte to pipe.
 			break;
 
-		if ( n < 0 && errno == EAGAIN )
-			// Success -- pipe is full and just need at least one byte in it.
-			break;
+		if ( n < 0 )
+			{
+			if ( errno == EAGAIN )
+				// Success: pipe is full and just need at least one byte in it.
+				break;
 
-		// Loop because either the byte wasn't written or got EINTR error.
+			if ( errno == EINTR )
+				// Interrupted: try again.
+				continue;
+
+			bad_pipe_op("write");
+			}
+
+		// No error, but didn't write a byte: try again.
 		}
 	}
 
@@ -37,7 +54,21 @@ void Flare::Extinguish()
 	char tmp[256];
 
 	for ( ; ; )
-		if ( read(pipe.ReadFD(), &tmp, sizeof(tmp)) == -1 && errno == EAGAIN )
-			// Pipe is now drained.
+		{
+		int n = read(pipe.ReadFD(), &tmp, sizeof(tmp));
+
+		if ( n >= 0 )
+			// Pipe may not be empty yet: try again.
+			continue;
+
+		if ( errno == EAGAIN )
+			// Success: pipe is now empty.
 			break;
+
+		if ( errno == EINTR )
+			// Interrupted: try again.
+			continue;
+
+		bad_pipe_op("read");
+		}
 	}