syzbot

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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

read-write to 0xffff888237d1ff94 of 4 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x72/0x4a0 kernel/time/hrtimer.c:1843
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1d0 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 batadv_check_known_mac_addr+0x4f/0x180 net/batman-adv/hard-interface.c:515
 batadv_hardif_add_interface net/batman-adv/hard-interface.c:906 [inline]
 batadv_hard_if_event+0xa06/0x1010 net/batman-adv/hard-interface.c:970
 notifier_call_chain kernel/notifier.c:93 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:461
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1996
 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
 call_netdevice_notifiers net/core/dev.c:2048 [inline]
 register_netdevice+0xca9/0xe30 net/core/dev.c:10528
 __ip_tunnel_create+0x1c5/0x270 net/ipv4/ip_tunnel.c:267
 ip_tunnel_init_net+0x18a/0x3e0 net/ipv4/ip_tunnel.c:1160
 erspan_init_net+0x35/0x40 net/ipv4/ip_gre.c:1756
 ops_init+0x1c9/0x260 net/core/net_namespace.c:139
 setup_net+0x14d/0x600 net/core/net_namespace.c:356
 copy_net_ns+0x290/0x430 net/core/net_namespace.c:494
 create_new_namespaces+0x228/0x430 kernel/nsproxy.c:110
 copy_namespaces+0x1ad/0x210 kernel/nsproxy.c:179
 copy_process+0xd82/0x1f90 kernel/fork.c:2378
 kernel_clone+0x167/0x5e0 kernel/fork.c:2787
 __do_sys_clone kernel/fork.c:2930 [inline]
 __se_sys_clone kernel/fork.c:2914 [inline]
 __x64_sys_clone+0xe8/0x120 kernel/fork.c:2914
 x64_sys_call+0x2d7e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d1ff94 of 4 bytes by task 4466 on cpu 0:
 print_cpu+0x348/0x670 kernel/time/timer_list.c:135
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x2d1/0x930 fs/seq_file.c:230
 proc_reg_read_iter+0x118/0x190 fs/proc/inode.c:299
 copy_splice_read+0x3a0/0x5d0 fs/splice.c:365
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00006f4b -> 0x00006f4c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4466 Comm: syz.3.389 Tainted: G        W          6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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