From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 14 Dec 2016 23:05:38 +0000 (-0800)
Subject: relay: check array offset before using it
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=9a29d0fbc2d9ad99fb8a981ab72548cc360e9d4c;p=openwrt%2Fstaging%2Fblogic.git

relay: check array offset before using it

Smatch complains that we started using the array offset before we
checked that it was valid.

Fixes: 017c59c042d0 ('relay: Use per CPU constructs for the relay channel buffer pointers')
Link: http://lkml.kernel.org/r/20161013084947.GC16198@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/relay.c b/kernel/relay.c
index da79a109dbeb..8f18d314a96a 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -809,11 +809,11 @@ void relay_subbufs_consumed(struct rchan *chan,
 {
 	struct rchan_buf *buf;
 
-	if (!chan)
+	if (!chan || cpu >= NR_CPUS)
 		return;
 
 	buf = *per_cpu_ptr(chan->buf, cpu);
-	if (cpu >= NR_CPUS || !buf || subbufs_consumed > chan->n_subbufs)
+	if (!buf || subbufs_consumed > chan->n_subbufs)
 		return;
 
 	if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed)