net: use sock_gen_put() when sk_state is TCP_TIME_WAIT

It is possible for a pointer of type struct inet_timewait_sock to be
returned from the functions __inet_lookup_established() and
__inet6_lookup_established(). This can cause a crash when the
returned pointer is of type struct inet_timewait_sock and
sock_put() is called on it. The following is a crash call stack that
shows sk->sk_wmem_alloc being accessed in sk_free() during the call to
sock_put() on a struct inet_timewait_sock pointer. To avoid this issue,
use sock_gen_put() instead of sock_put() when sk->sk_state
is TCP_TIME_WAIT.

mrdump.ko        ipanic() + 120
vmlinux          notifier_call_chain(nr_to_call=-1, nr_calls=0) + 132
vmlinux          atomic_notifier_call_chain(val=0) + 56
vmlinux          panic() + 344
vmlinux          add_taint() + 164
vmlinux          end_report() + 136
vmlinux          kasan_report(size=0) + 236
vmlinux          report_tag_fault() + 16
vmlinux          do_tag_recovery() + 16
vmlinux          __do_kernel_fault() + 88
vmlinux          do_bad_area() + 28
vmlinux          do_tag_check_fault() + 60
vmlinux          do_mem_abort() + 80
vmlinux          el1_abort() + 56
vmlinux          el1h_64_sync_handler() + 124
vmlinux        > 0xFFFFFFC080011294()
vmlinux          __lse_atomic_fetch_add_release(v=0xF2FFFF82A896087C)
vmlinux          __lse_atomic_fetch_sub_release(v=0xF2FFFF82A896087C)
vmlinux          arch_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C)
+ 8
vmlinux          raw_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C)
+ 8
vmlinux          atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C) + 8
vmlinux          __refcount_sub_and_test(i=1, r=0xF2FFFF82A896087C,
oldp=0) + 8
vmlinux          __refcount_dec_and_test(r=0xF2FFFF82A896087C, oldp=0) + 8
vmlinux          refcount_dec_and_test(r=0xF2FFFF82A896087C) + 8
vmlinux          sk_free(sk=0xF2FFFF82A8960700) + 28
vmlinux          sock_put() + 48
vmlinux          tcp6_check_fraglist_gro() + 236
vmlinux          tcp6_gro_receive() + 624
vmlinux          ipv6_gro_receive() + 912
vmlinux          dev_gro_receive() + 1116
vmlinux          napi_gro_receive() + 196
ccmni.ko         ccmni_rx_callback() + 208
ccmni.ko         ccmni_queue_recv_skb() + 388
ccci_dpmaif.ko   dpmaif_rxq_push_thread() + 1088
vmlinux          kthread() + 268
vmlinux          0xFFFFFFC08001F30C()

Fixes: c9d1d23 ("net: add heuristic for enabling TCP fraglist GRO")
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250429020412.14163-1-shiming.cheng@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/tcp_offload.c

@@ -439,7 +439,7 @@ static void tcp4_check_fraglist_gro(struct list_head *head, struct sk_buff *skb,
 				       iif, sdif);
 	NAPI_GRO_CB(skb)->is_flist = !sk;
 	if (sk)
-		sock_put(sk);
+		sock_gen_put(sk);
 }
 
 INDIRECT_CALLABLE_SCOPE

net/ipv6/tcpv6_offload.c

@@ -42,7 +42,7 @@ static void tcp6_check_fraglist_gro(struct list_head *head, struct sk_buff *skb,
 					iif, sdif);
 	NAPI_GRO_CB(skb)->is_flist = !sk;
 	if (sk)
-		sock_put(sk);
+		sock_gen_put(sk);
 #endif /* IS_ENABLED(CONFIG_IPV6) */
 }