From 5549d0493d6f60f4ed429ee2c893ed2129118fb9 Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Mon, 1 Jun 2015 12:18:39 +0200
Subject: [PATCH] sys: newlib: remove _read_r() race

---
 sys/newlib/syscalls.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/sys/newlib/syscalls.c b/sys/newlib/syscalls.c
index a6aa78272e1d..29c3058daa2d 100644
--- a/sys/newlib/syscalls.c
+++ b/sys/newlib/syscalls.c
@@ -203,11 +203,13 @@ int _open_r(struct _reent *r, const char *name, int mode)
 int _read_r(struct _reent *r, int fd, void *buffer, unsigned int count)
 {
 #ifndef MODULE_UART0
+    int res;
     mutex_lock(&uart_rx_mutex);
-
+    unsigned state = disableIRQ();
     count = count < rx_buf.avail ? count : rx_buf.avail;
-
-    return ringbuffer_get(&rx_buf, (char*)buffer, count);
+    res = ringbuffer_get(&rx_buf, (char*)buffer, count);
+    restoreIRQ(state);
+    return res;
 #else
     char *res = (char*)buffer;
     res[0] = (char)uart0_readc();