[syzbot] [lsm?] [net?] WARNING in kvfree_call_rcu

[Kuniyuki Iwashima]

From: syzbot <syzbot+40bf00346c3fe40f90f2 at syzkaller.appspotmail.com>
Date: Tue, 08 Jul 2025 15:54:02 -0700
> Hello,
> 
> syzbot tried to test the proposed patch but the build/boot failed:
> 
> net/smc/af_smc.c:365:3: error: call to undeclared function 'inet_sock_destruct'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>

#syz test

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 3760131f14845..1882bab8e00e7 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -30,6 +30,10 @@
 #include <linux/splice.h>
 
 #include <net/sock.h>
+#include <net/inet_common.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#endif
 #include <net/tcp.h>
 #include <net/smc.h>
 #include <asm/ioctls.h>
@@ -360,6 +364,16 @@ static void smc_destruct(struct sock *sk)
 		return;
 	if (!sock_flag(sk, SOCK_DEAD))
 		return;
+	switch (sk->sk_family) {
+	case AF_INET:
+		inet_sock_destruct(sk);
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case AF_INET6:
+		inet6_sock_destruct(sk);
+		break;
+#endif
+	}
 }
 
 static struct lock_class_key smc_key;
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 78ae10d06ed2e..cc59d0f03e261 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -283,7 +283,10 @@ struct smc_connection {
 };
 
 struct smc_sock {				/* smc sock container */
-	struct sock		sk;
+	union {
+		struct sock		sk;
+		struct inet_sock	icsk_inet;
+	};
 #if IS_ENABLED(CONFIG_IPV6)
 	struct ipv6_pinfo	*pinet6;
 #endif