[patch net] net: sched: fix possible null pointer deref in tcf_block_put

[Jiri Pirko]

From: Jiri Pirko <j...@mellanox.com>

We need to check block for being null in both tcf_block_put and
tcf_block_put_ext.

Fixes: 343723dd51ef ("net: sched: fix clsact init error path")
Reported-by: Prashant Bhole <bhole_prashant...@lab.ntt.co.jp>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 net/sched/cls_api.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index b91ea03..b9d63d2 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -379,6 +379,8 @@ void tcf_block_put(struct tcf_block *block)
 {
        struct tcf_block_ext_info ei = {0, };
 
+       if (!block)
+               return;
        tcf_block_put_ext(block, block->q, &ei);
 }
 
-- 
2.9.5