From: Anton Blanchard <anton@samba.org>
Date: Mon, 10 Nov 2014 22:12:28 +0000 (+1100)
Subject: powerpc: Fix bad NULL pointer check in udbg_uart_getc_poll()
X-Git-Tag: v3.14.29~59
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3d352acf5b50f58c1c0f5b2d616790f450747436;p=platform%2Fkernel%2Flinux-stable.git

powerpc: Fix bad NULL pointer check in udbg_uart_getc_poll()

commit cd32e2dcc9de6c27ecbbfc0e2079fb64b42bad5f upstream.

We have some code in udbg_uart_getc_poll() that tries to protect
against a NULL udbg_uart_in, but gets it all wrong.

Found with the LLVM static analyzer (scan-build).

Fixes: 309257484cc1 ("powerpc: Cleanup udbg_16550 and add support for LPC PIO-only UARTs")
Signed-off-by: Anton Blanchard <anton@samba.org>
[mpe: Add some newlines for readability while we're here]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index 75702e207b29..f7089fcfaa5d 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -69,8 +69,12 @@ static void udbg_uart_putc(char c)
 
 static int udbg_uart_getc_poll(void)
 {
-	if (!udbg_uart_in || !(udbg_uart_in(UART_LSR) & LSR_DR))
+	if (!udbg_uart_in)
+		return -1;
+
+	if (!(udbg_uart_in(UART_LSR) & LSR_DR))
 		return udbg_uart_in(UART_RBR);
+
 	return -1;
 }