From: Yajun Deng <yajun.deng@linux.dev> stable inclusion from stable-v5.10.96 commit 9b4444197252bec2f3248b3e4fff11a5d571c19e bugzilla: https://gitee.com/openeuler/kernel/issues/I55NWB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 1b9fbe813016b08e08b22ddba4ddbf9cb1b04b00 ] Add a if statements to avoid the warning. Dan Carpenter report: The patch faf482ca196a: "net: ipv4: Move ip_options_fragment() out of loop" from Aug 23, 2021, leads to the following Smatch complaint: net/ipv4/ip_output.c:833 ip_do_fragment() warn: variable dereferenced before check 'iter.frag' (see line 828) Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: faf482ca196a ("net: ipv4: Move ip_options_fragment() out of loop") Link: https://lore.kernel.org/netdev/20210830073802.GR7722@kadam/T/#t Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- net/ipv4/ip_output.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index fb91a466b2d3..e77afaecc981 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -833,7 +833,9 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, /* Everything is OK. Generate! */ ip_fraglist_init(skb, iph, hlen, &iter); - ip_options_fragment(iter.frag); + + if (iter.frag) + ip_options_fragment(iter.frag); for (;;) { /* Prepare header of the next frame, -- 2.20.1