[ARM] Fix stacktrace FP range checking
Fix an oops in the stacktrace code, caused by improper range checking.
We subtract 12 off 'fp' before testing to see if it's below the low
bound. However, if 'fp' were zero before, it becomes a very large
positive number, causing this test to succeed where it should fail.
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 8b63ad8..ae31deb 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -13,7 +13,7 @@
/*
* Check current frame pointer is within bounds
*/
- if ((fp - 12) < low || fp + 4 >= high)
+ if (fp < (low + 12) || fp + 4 >= high)
break;
frame = (struct stackframe *)(fp - 12);