TCP: request_sock_TCP: Possible SYN flooding on port [::]:20002. Sending cookies.
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BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in smc_tcp_syn_recv_sock+0x92/0x3d0 net/smc/af_smc.c:131
Read of size 4 at addr 00000000000009d4 by task syz.0.3076/17682

CPU: 1 UID: 0 PID: 17682 Comm: syz.0.3076 Not tainted 6.12.0-next-20241122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_report+0xe8/0x550 mm/kasan/report.c:492
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 smc_tcp_syn_recv_sock+0x92/0x3d0 net/smc/af_smc.c:131
 tcp_get_cookie_sock+0xfd/0x780 net/ipv4/syncookies.c:204
 cookie_v4_check+0x1601/0x22b0 net/ipv4/syncookies.c:485
 tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1865 [inline]
 tcp_v4_do_rcv+0x6cd/0xc70 net/ipv4/tcp_ipv4.c:1924
 tcp_v4_rcv+0x2b00/0x37f0 net/ipv4/tcp_ipv4.c:2341
 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5672 [inline]
 __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5785
 process_backlog+0x662/0x15b0 net/core/dev.c:6117
 __napi_poll+0xcb/0x490 net/core/dev.c:6877
 napi_poll net/core/dev.c:6946 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7068
 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0x1775/0x3f50 net/core/dev.c:4461
 dev_queue_xmit include/linux/netdevice.h:3168 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236
 ip_local_out net/ipv4/ip_output.c:130 [inline]
 __ip_queue_xmit+0x12ca/0x1ef0 net/ipv4/ip_output.c:536
 __tcp_transmit_skb+0x2582/0x3ba0 net/ipv4/tcp_output.c:1466
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6576 [inline]
 tcp_rcv_state_process+0x2b9d/0x44e0 net/ipv4/tcp_input.c:6770
 tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1939
 sk_backlog_rcv include/net/sock.h:1121 [inline]
 __release_sock+0x214/0x350 net/core/sock.c:3083
 release_sock+0x61/0x1f0 net/core/sock.c:3637
 mptcp_connect+0x7e4/0xb20 net/mptcp/protocol.c:3807
 __inet_stream_connect+0x262/0xf30 net/ipv4/af_inet.c:677
 inet_stream_connect+0x65/0xa0 net/ipv4/af_inet.c:748
 __sys_connect_file net/socket.c:2055 [inline]
 __sys_connect+0x288/0x2d0 net/socket.c:2074
 __do_sys_connect net/socket.c:2080 [inline]
 __se_sys_connect net/socket.c:2077 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2077
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f727817e819
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7278ee1038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f7278335fa0 RCX: 00007f727817e819
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000006
RBP: 00007f72781f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7278335fa0 R15: 00007ffebbb0af18
 </TASK>
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