From: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Date: Thu, 5 Dec 2013 13:23:48 +0000 (+0100)
Subject: ARM: 7913/1: fix framepointer check in unwind_frame
X-Git-Tag: v3.13-rc4~9^2~2
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=3abb6671a9c04479c4bd026798a05f857393b7e2

ARM: 7913/1: fix framepointer check in unwind_frame

This patch fixes corner case when (fp + 4) overflows unsigned long,
for example: fp = 0xFFFFFFFF -> fp + 4 == 3.

Cc: <stable@vger.kernel.org>
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 00f79e59985b..af4e8c8a5422 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -31,7 +31,7 @@ int notrace unwind_frame(struct stackframe *frame)
 	high = ALIGN(low, THREAD_SIZE);
 
 	/* check current frame pointer is within bounds */
-	if (fp < (low + 12) || fp + 4 >= high)
+	if (fp < low + 12 || fp > high - 4)
 		return -EINVAL;
 
 	/* restore the registers from the stack frame */