[PATCH] net: smc: fix error return code of smc_diag_dump_proto()

When the list of head is empty, no error return code of
smc_diag_dump_proto() is assigned.
To fix this bug, rc is assigned with -ENOENT as error return code.

Reported-by: TOTE Robot <redacted>
Signed-off-by: Jia-Ju Bai <redacted>
---
 net/smc/smc_diag.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index c952986a6aca..a90889482842 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c

@@ -201,8 +201,10 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb,
 
 	read_lock(&prot->h.smc_hash->lock);
 	head = &prot->h.smc_hash->ht;
-	if (hlist_empty(head))
+	if (hlist_empty(head)) {
+		rc = -ENOENT;
 		goto out;
+	}
 
 	sk_for_each(sk, head) {
 		if (!net_eq(sock_net(sk), net))

-- 
2.17.1

On 05/03/2021 11:13, Jia-Ju Bai wrote:

When the list of head is empty, no error return code of
smc_diag_dump_proto() is assigned.
To fix this bug, rc is assigned with -ENOENT as error return code.

Your change would break smc_diag_dump().
When there are no IPv4 sockets (SMCPROTO_SMC) in the list and -ENOENT 
is returned then smc_diag_dump() will not try to dump any IPv6 sockets
(SMCPROTO_SMC6). Returning zero is correct here.

-- 
Karsten

(I'm a dude)