netdev - [PATCH bpf-next v2] bpf: silence uninitialized var warning in bpf_skb_net

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Date:   Sat, 23 Mar 2019 12:23:07 -0400
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     netdev@...r.kernel.org
Cc:     ast@...nel.org, daniel@...earbox.net,
        Willem de Bruijn <willemb@...gle.com>,
        kbuild test robot <lkp@...el.com>
Subject: [PATCH bpf-next v2] bpf: silence uninitialized var warning in bpf_skb_net_grow

From: Willem de Bruijn <willemb@...gle.com>

These three variables are set in one branch and used in another with
the same condition. But on some architectures they still generate
compiler warnings of the kind:

  warning: 'inner_trans' may be used uninitialized in this function [-Wmaybe-uninitialized]

Silence these false positives. Use the straightforward approach to
always initialize them, if a bit superfluous.

Fixes: 868d523535c2 ("bpf: add bpf_skb_adjust_room encap flags")
Reported-by: kbuild test robot <lkp@...el.com>
Signed-off-by: Willem de Bruijn <willemb@...gle.com>

--
v1->v2: add missing word in fixes tag
---
 net/core/filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 0a972fbf60df..22eb2edf5573 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2975,8 +2975,8 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff,
 			    u64 flags)
 {
 	bool encap = flags & BPF_F_ADJ_ROOM_ENCAP_L3_MASK;
+	u16 mac_len = 0, inner_net = 0, inner_trans = 0;
 	unsigned int gso_type = SKB_GSO_DODGY;
-	u16 mac_len, inner_net, inner_trans;
 	int ret;
 
 	if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) {
-- 
2.21.0.392.gf8f6787159e-goog