[PATCH 1/2] ras: fix an off-by-one error in __find_elem()

[Cong Wang]

ce_arr.array[] is always within the range [0, ce_arr.n-1].
However, the binary search code in __find_elem() uses ce_arr.n
as the maximum index, which could lead to an off-by-one
out-of-bound access when the element after the last is exactly
the one just got deleted, that is, 'min' returned to caller as
'ce_arr.n'.

Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector")
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
---
 drivers/ras/cec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 2d9ec378a8bc..61332c9aab5a 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -184,7 +184,7 @@ static void cec_timer_fn(struct timer_list *unused)
 static int __find_elem(struct ce_array *ca, u64 pfn, unsigned int *to)
 {
 	u64 this_pfn;
-	int min = 0, max = ca->n;
+	int min = 0, max = ca->n - 1;
 
 	while (min < max) {
 		int tmp = (max + min) >> 1;
-- 
2.20.1