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+0x92/0x420 net/smc/af_smc.c:131
Read of size 4 at addr 00000000000009dc by task syz.1.132/6481

CPU: 0 UID: 0 PID: 6481 Comm: syz.1.132 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x29a/0x2b0 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:131
 tcp_check_req+0xf0e/0x1800 net/ipv4/tcp_minisocks.c:871
 tcp_v4_rcv+0x184f/0x2ef0 net/ipv4/tcp_ipv4.c:2283
 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2fb/0x580 net/ipv4/ip_input.c:233
 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:314
 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5887 [inline]
 __netif_receive_skb+0x143/0x380 net/core/dev.c:6000
 process_backlog+0x60e/0x14f0 net/core/dev.c:6352
 __napi_poll+0xc4/0x480 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0x6ea/0xdf0 net/core/dev.c:7510
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __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+0x1cd7/0x3a70 net/core/dev.c:4656
 dev_queue_xmit include/linux/netdevice.h:3350 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip_finish_output2+0xd03/0x1160 net/ipv4/ip_output.c:235
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0x1101/0x1b00 net/ipv4/ip_output.c:527
 __tcp_transmit_skb+0x225c/0x36c0 net/ipv4/tcp_output.c:1479
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6623 [inline]
 tcp_rcv_state_process+0x2283/0x4190 net/ipv4/tcp_input.c:6817
 tcp_v4_do_rcv+0x3f2/0xce0 net/ipv4/tcp_ipv4.c:1948
 sk_backlog_rcv include/net/sock.h:1132 [inline]
 __release_sock+0x21c/0x350 net/core/sock.c:3163
 release_sock+0x5f/0x1f0 net/core/sock.c:3717
 mptcp_connect+0x81a/0xc10 net/mptcp/protocol.c:3691
 __inet_stream_connect+0x298/0xf10 net/ipv4/af_inet.c:677
 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:748
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe220f8e969
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:00007fe221df0038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fe2211b5fa0 RCX: 00007fe220f8e969
RDX: 0000000000000010 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fe221010ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe2211b5fa0 R15: 00007fe2212dfa28
 </TASK>
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vkms_vblank_simulate: vblank timer overrun