================================================================== 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+0x92/0x420 net/smc/af_smc.c:135 Read of size 4 at addr 0000000000000ab4 by task syz.2.27/6087 CPU: 1 UID: 0 PID: 6087 Comm: syz.2.27 Not tainted 6.17.0-rc2-next-20250818-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: 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: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+0x92/0x420 net/smc/af_smc.c:135 tcp_check_req+0xf11/0x1800 net/ipv4/tcp_minisocks.c:874 tcp_v4_rcv+0x1896/0x2f40 net/ipv4/tcp_ipv4.c:2291 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+0x309/0x3a0 include/linux/netfilter.h:318 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:5979 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6092 process_backlog+0x60e/0x14f0 net/core/dev.c:6444 __napi_poll+0xc7/0x360 net/core/dev.c:7494 napi_poll net/core/dev.c:7557 [inline] net_rx_action+0x707/0xe30 net/core/dev.c:7684 handle_softirqs+0x283/0x870 kernel/softirq.c:579 do_softirq+0xec/0x180 kernel/softirq.c:480 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:910 [inline] __dev_queue_xmit+0x1d79/0x3b50 net/core/dev.c:4740 dev_queue_xmit include/linux/netdevice.h:3361 [inline] neigh_hh_output include/net/neighbour.h:531 [inline] neigh_output include/net/neighbour.h:545 [inline] ip_finish_output2+0xd03/0x1160 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x2a1/0x3c0 net/ipv4/ip_output.c:436 ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x1106/0x1b00 net/ipv4/ip_output.c:532 __tcp_transmit_skb+0x2215/0x3680 net/ipv4/tcp_output.c:1479 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6527 [inline] tcp_rcv_state_process+0x2a99/0x4140 net/ipv4/tcp_input.c:6721 tcp_v4_do_rcv+0x3f2/0xce0 net/ipv4/tcp_ipv4.c:1949 sk_backlog_rcv include/net/sock.h:1148 [inline] __release_sock+0x21c/0x350 net/core/sock.c:3194 release_sock+0x5f/0x1f0 net/core/sock.c:3748 mptcp_connect+0x649/0x830 net/mptcp/protocol.c:3751 __inet_stream_connect+0x2ab/0xe80 net/ipv4/af_inet.c:677 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:748 __sys_connect_file net/socket.c:2086 [inline] __sys_connect+0x313/0x440 net/socket.c:2105 __do_sys_connect net/socket.c:2111 [inline] __se_sys_connect net/socket.c:2108 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2108 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f103d78ebe9 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:00007f103e659038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f103d9b5fa0 RCX: 00007f103d78ebe9 RDX: 0000000000000010 RSI: 0000200000000000 RDI: 0000000000000006 RBP: 00007f103d811e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f103d9b6038 R14: 00007f103d9b5fa0 R15: 00007ffe3d39d818 ==================================================================