[PATCH 4.9 131/206] relay: check array offset before using it
From: Greg Kroah-Hartman
Date: Tue Jan 10 2017 - 08:49:38 EST
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
commit 9a29d0fbc2d9ad99fb8a981ab72548cc360e9d4c upstream.
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@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/relay.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -809,11 +809,11 @@ void relay_subbufs_consumed(struct rchan
{
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)