diff --git a/src/pages.c b/src/pages.c
index 0883647b..f8ef2bcb 100644
--- a/src/pages.c
+++ b/src/pages.c
@@ -358,7 +358,9 @@ os_overcommits_proc(void) {
 			O_CLOEXEC);
 	#else
 		fd = (int)syscall(SYS_open, "/proc/sys/vm/overcommit_memory", O_RDONLY);
-		fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		if (fd != -1) {
+			fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		}
 	#endif
 #elif defined(JEMALLOC_USE_SYSCALL) && defined(SYS_openat)
 	#if defined(O_CLOEXEC)
@@ -367,14 +369,18 @@ os_overcommits_proc(void) {
 	#else
 		fd = (int)syscall(SYS_openat,
 			AT_FDCWD, "/proc/sys/vm/overcommit_memory", O_RDONLY);
-		fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		if (fd != -1) {
+			fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		}
 	#endif
 #else
 	#if defined(O_CLOEXEC)
 		fd = open("/proc/sys/vm/overcommit_memory", O_RDONLY | O_CLOEXEC);
 	#else
 		fd = open("/proc/sys/vm/overcommit_memory", O_RDONLY);
-		fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		if (fd != -1) {
+			fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+		}
 	#endif
 #endif
 
diff --git a/src/prof.c b/src/prof.c
index a1ca9e2c..32760e68 100644
--- a/src/prof.c
+++ b/src/prof.c
@@ -1414,7 +1414,9 @@ prof_open_maps(const char *format, ...) {
 	mfd = open(filename, O_RDONLY | O_CLOEXEC);
 #else
 	mfd = open(filename, O_RDONLY);
-	fcntl(mfd, F_SETFD, fcntl(mfd, F_GETFD) | FD_CLOEXEC);
+	if (mfd != -1) {
+		fcntl(mfd, F_SETFD, fcntl(mfd, F_GETFD) | FD_CLOEXEC);
+	}
 #endif
 
 	return mfd;