diff --git a/src/stdio/__stdio_close.c b/src/stdio/__stdio_close.c
index 30291328..fd46b09f 100644
--- a/src/stdio/__stdio_close.c
+++ b/src/stdio/__stdio_close.c
@@ -10,5 +10,7 @@ weak_alias(dummy, __aio_close);
 
 int __stdio_close(FILE *f)
 {
-	return syscall(SYS_close, __aio_close(f->fd));
+	int fd = f->fd;
+	f->fd = -1;
+	return syscall(SYS_close, __aio_close(fd));
 }
diff --git a/src/stdio/popen.c b/src/stdio/popen.c
index 3ec83394..9a7388f3 100644
--- a/src/stdio/popen.c
+++ b/src/stdio/popen.c
@@ -34,9 +34,14 @@ FILE *popen(const char *cmd, const char *mode)
 
 	e = ENOMEM;
 	if (!posix_spawn_file_actions_init(&fa)) {
-		for (FILE *l = *__ofl_lock(); l; l=l->next)
-			if (l->pipe_pid && posix_spawn_file_actions_addclose(&fa, l->fd))
+		for (FILE *l = *__ofl_lock(); l; l=l->next) {
+			if (!l->pipe_pid) continue;
+			FLOCK(l);
+			int t = l->fd;
+			FUNLOCK(l);
+			if (t>=0 && posix_spawn_file_actions_addclose(&fa, t))
 				goto fail;
+		}
 		if (!posix_spawn_file_actions_adddup2(&fa, p[1-op], 1-op)) {
 			if (!(e = posix_spawn(&pid, "/bin/sh", &fa, 0,
 			    (char *[]){ "sh", "-c", (char *)cmd, 0 }, __environ))) {