ARM: 7913/1: fix framepointer check in unwind_frame

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 00f79e5..af4e8c8 100644 (file)
--- 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 */