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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff888237c1b2a0 of 8 bytes by interrupt on cpu 0:
 hrtimer_interrupt+0x22f/0x460 kernel/time/hrtimer.c:1911
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 arch_atomic64_read arch/x86/include/asm/atomic64_64.h:15 [inline]
 raw_atomic64_read include/linux/atomic/atomic-arch-fallback.h:2583 [inline]
 raw_atomic_long_read include/linux/atomic/atomic-long.h:38 [inline]
 atomic_long_read include/linux/atomic/atomic-instrumented.h:3189 [inline]
 find_watchpoint kernel/kcsan/core.c:131 [inline]
 check_access kernel/kcsan/core.c:737 [inline]
 __tsan_read8+0x39/0x190 kernel/kcsan/core.c:1025
 xt_get_this_cpu_counter include/linux/netfilter/x_tables.h:426 [inline]
 ipt_do_table+0x683/0xab0 net/ipv4/netfilter/ip_tables.c:297
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0x78/0x180 net/netfilter/core.c:623
 nf_hook_slow_list+0xed/0x200 net/netfilter/core.c:660
 NF_HOOK_LIST include/linux/netfilter.h:354 [inline]
 ip_sublist_rcv+0x6a0/0x6c0 net/ipv4/ip_input.c:642
 ip_list_rcv+0x261/0x290 net/ipv4/ip_input.c:678
 __netif_receive_skb_list_ptype net/core/dev.c:6122 [inline]
 __netif_receive_skb_list_core+0x4dc/0x500 net/core/dev.c:6169
 __netif_receive_skb_list net/core/dev.c:6221 [inline]
 netif_receive_skb_list_internal+0x487/0x600 net/core/dev.c:6312
 netif_receive_skb_list+0x31/0x200 net/core/dev.c:6364
 xdp_recv_frames net/bpf/test_run.c:280 [inline]
 xdp_test_run_batch net/bpf/test_run.c:361 [inline]
 bpf_test_run_xdp_live+0xe75/0x1050 net/bpf/test_run.c:390
 bpf_prog_test_run_xdp+0x59a/0x970 net/bpf/test_run.c:1331
 bpf_prog_test_run+0x22a/0x390 kernel/bpf/syscall.c:4673
 __sys_bpf+0x4c0/0x7c0 kernel/bpf/syscall.c:6152
 __do_sys_bpf kernel/bpf/syscall.c:6244 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6242 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6242
 x64_sys_call+0x2aee/0x3000 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c1b2a0 of 8 bytes by task 12626 on cpu 1:
 print_cpu+0x2ea/0x660 kernel/time/timer_list.c:131
 timer_list_show+0x107/0x170 kernel/time/timer_list.c:293
 seq_read_iter+0x636/0x950 fs/seq_file.c:272
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7fffffffffffffff -> 0x0000001cd9a14fad

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12626 Comm: syz.4.1653 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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