[PATCH v3 2/2] nfc: llcp: stop processing on LLCP_CLOSED in nfc_llcp_recv_hdlc()

[Qianchang Zhao <pioooooooooip@gmail.com>]

nfc_llcp_sock_get() takes a reference on the LLCP socket via sock_hold().

In nfc_llcp_recv_hdlc(), the LLCP_CLOSED branch releases the socket lock
and drops the reference, but the function continues to operate on
llcp_sock/sk and later runs release_sock() and nfc_llcp_sock_put() again
on the common exit path.	

Return immediately after the CLOSED cleanup to avoid refcount/lock 
imbalance and to avoid using the socket after dropping the reference.

Fixes: d646960f7986 ("NFC: Initial LLCP support")
Cc: stable@vger.kernel.org
Signed-off-by: Qianchang Zhao <pioooooooooip@gmail.com>
---
 net/nfc/llcp_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
index ed37604ed..f6c1d79f9 100644
--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -1089,6 +1089,7 @@ static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local,
 	if (sk->sk_state == LLCP_CLOSED) {
 		release_sock(sk);
 		nfc_llcp_sock_put(llcp_sock);
+		return;
 	}
 
 	/* Pass the payload upstream */
-- 
2.34.1