[PATCH 3.8 029/166] ARM: 7913/1: fix framepointer check in unwind_frame

Kamal Mostafa
2014-01-15T21:50:43Z

From: Konstantin Khlebnikov <k.khlebnikov@samsung.com>

commit 3abb6671a9c04479c4bd026798a05f857393b7e2 upstream.

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

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
arch/arm/kernel/stacktrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 00f79e5..af4e8c8 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 */
--
1.8.3.2