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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff888237c197e0 of 8 bytes by interrupt on cpu 0:
 hrtimer_interrupt+0x1fb/0xaf0 kernel/time/hrtimer.c:1803
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x1c0 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x64/0x80 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 __sanitizer_cov_trace_pc+0x0/0x60
 skb_free_head net/core/skbuff.c:654 [inline]
 skb_release_data+0x32c/0x370 net/core/skbuff.c:676
 skb_release_all net/core/skbuff.c:741 [inline]
 __kfree_skb+0x3b/0x150 net/core/skbuff.c:755
 kfree_skb+0x4d/0x130 net/core/skbuff.c:773
 sit_tunnel_xmit+0x9d6/0x1200
 __netdev_start_xmit include/linux/netdevice.h:4988 [inline]
 netdev_start_xmit include/linux/netdevice.h:5002 [inline]
 xmit_one+0xf9/0x270 net/core/dev.c:3576
 dev_hard_start_xmit net/core/dev.c:3592 [inline]
 __dev_queue_xmit+0x6e9/0xaa0 net/core/dev.c:4202
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4235
 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1521
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0x91e/0xb10 net/ipv6/ip6_output.c:126
 ip6_fragment+0xe39/0x1350 net/ipv6/ip6_output.c:907
 __ip6_finish_output net/ipv6/ip6_output.c:189 [inline]
 ip6_finish_output+0x444/0x480 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:450 [inline]
 ip6_local_out+0x121/0x1e0 net/ipv6/output_core.c:161
 ip6_send_skb+0x43/0xf0 net/ipv6/ip6_output.c:1912
 udp_v6_send_skb+0x798/0x9f0 net/ipv6/udp.c:1249
 udpv6_sendmsg+0x1664/0x16e0 net/ipv6/udp.c:1547
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:643
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmmsg+0x388/0x520 net/socket.c:2549
 __do_sys_sendmmsg net/socket.c:2578 [inline]
 __se_sys_sendmmsg net/socket.c:2575 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c197e0 of 8 bytes by task 24570 on cpu 1:
 print_cpu+0x32e/0x690 kernel/time/timer_list.c:133
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:291
 seq_read_iter+0x2e1/0x930 fs/seq_file.c:230
 proc_reg_read_iter+0xfc/0x170 fs/proc/inode.c:300
 call_read_iter include/linux/fs.h:2157 [inline]
 generic_file_splice_read+0x24f/0x330 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1314 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000064886659b6 -> 0x7fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24570 Comm: syz-executor.3 Tainted: G        W         5.15.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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