[PATCH mptcp-net 2/2] mptcp: options: dss: avoid printing uninit csum

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

When parsing the DSS suboption, this pr_debug() might read and print
uninit checksum value.

That's mostly harmless, but that's also confusing. Fixing that also
avoids some tools to complain about accessing unint data.

So read this csum field only if it has been set.

Fixes: 390b95a5fb84 ("mptcp: receive checksum for DSS")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/options.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 7f7ed4753100..20490410fa22 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -259,7 +259,7 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 			pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u\n",
 				 mp_opt->data_seq, mp_opt->subflow_seq,
 				 mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD),
-				 mp_opt->csum);
+				 (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) ? mp_opt->csum : 0);
 		}
 
 		break;

-- 
2.55.0