syzbot

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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+0x92/0x4b0 net/smc/af_smc.c:134
Read of size 4 at addr 0000000000000d94 by task syz.3.39/6078

CPU: 0 UID: 0 PID: 6078 Comm: syz.3.39 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 smc_tcp_syn_recv_sock+0x92/0x4b0 net/smc/af_smc.c:134
 tcp_check_req+0x109e/0x1a90 net/ipv4/tcp_minisocks.c:912
 tcp_v4_rcv+0x17b8/0x2f20 net/ipv4/tcp_ipv4.c:2297
 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6079 [inline]
 __netif_receive_skb+0x143/0x380 net/core/dev.c:6192
 process_backlog+0x31e/0x900 net/core/dev.c:6544
 __napi_poll+0xb6/0x540 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0x5f7/0xda0 net/core/dev.c:7784
 handle_softirqs+0x22f/0x710 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 __dev_queue_xmit+0x1d3d/0x3b70 net/core/dev.c:4790
 dev_queue_xmit include/linux/netdevice.h:3365 [inline]
 neigh_hh_output include/net/neighbour.h:531 [inline]
 neigh_output include/net/neighbour.h:545 [inline]
 ip_finish_output2+0xd5a/0x11d0 net/ipv4/ip_output.c:237
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
 ip_local_out net/ipv4/ip_output.c:131 [inline]
 __ip_queue_xmit+0x118d/0x1c30 net/ipv4/ip_output.c:534
 __tcp_transmit_skb+0x24f6/0x3aa0 net/ipv4/tcp_output.c:1628
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6761 [inline]
 tcp_rcv_state_process+0x2d62/0x44d0 net/ipv4/tcp_input.c:6955
 tcp_v4_do_rcv+0xa25/0x12b0 net/ipv4/tcp_ipv4.c:1954
 sk_backlog_rcv include/net/sock.h:1158 [inline]
 __release_sock+0x285/0x3e0 net/core/sock.c:3180
 release_sock+0x75/0x210 net/core/sock.c:3735
 mptcp_connect+0x649/0x830 net/mptcp/protocol.c:3809
 __inet_stream_connect+0x2ae/0xe70 net/ipv4/af_inet.c:679
 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:750
 __sys_connect_file net/socket.c:2102 [inline]
 __sys_connect+0x323/0x450 net/socket.c:2121
 __do_sys_connect net/socket.c:2127 [inline]
 __se_sys_connect net/socket.c:2124 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2124
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcafdefefc9
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:00007fcafc13d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fcafe156090 RCX: 00007fcafdefefc9
RDX: 0000000000000010 RSI: 0000200000000000 RDI: 0000000000000007
RBP: 00007fcafdf81f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcafe156128 R14: 00007fcafe156090 R15: 00007ffff0e3a738
 </TASK>
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