netdev - [PATCH net-next] bpf: dev_map_alloc() shouldn't return NULL

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Date:   Sat, 22 Jul 2017 10:40:04 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        John Fastabend <john.fastabend@...il.com>
Cc:     Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH net-next] bpf: dev_map_alloc() shouldn't return NULL

We forgot to set the error code on two error paths which means that we
return ERR_PTR(0) which is NULL.  The caller, find_and_alloc_map(), is
not expecting that and will have a NULL dereference.

Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 899364d097f5..d439ee0eadb1 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -114,6 +114,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
 	if (err)
 		goto free_dtab;
 
+	err = -ENOMEM;
 	/* A per cpu bitfield with a bit per possible net device */
 	dtab->flush_needed = __alloc_percpu(
 				BITS_TO_LONGS(attr->max_entries) *