[patch] relay: check array offset before using it

From: Dan Carpenter
Date: Thu Oct 13 2016 - 04:52:24 EST


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')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/kernel/relay.c b/kernel/relay.c
index da79a10..8f18d31 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)