syzbot

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BUG: KCSAN: data-race in clockevents_program_event / print_tickdevice

write to 0xffff888237c179e0 of 8 bytes by task 4510 on cpu 0:
 clockevents_program_event+0x46/0x340 kernel/time/clockevents.c:347
 tick_program_event+0x79/0xc0 kernel/time/tick-oneshot.c:48
 hrtimer_rearm_event kernel/time/hrtimer.c:707 [inline]
 hrtimer_rearm kernel/time/hrtimer.c:2141 [inline]
 __hrtimer_rearm_deferred+0x569/0x650 kernel/time/hrtimer.c:2161
 hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:53 [inline]
 hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:62 [inline]
 irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:505 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:542 [inline]
 irqentry_exit+0x58f/0x610 kernel/entry/common.c:167
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __tsan_read1+0x12/0x180 kernel/kcsan/core.c:1022
 strlen+0x19/0x40 lib/string.c:402
 __fortify_strlen include/linux/fortify-string.h:218 [inline]
 insert_entry fs/proc/proc_sysctl.c:167 [inline]
 insert_header+0x695/0x970 fs/proc/proc_sysctl.c:252
 __register_sysctl_table+0xb60/0xbe0 fs/proc/proc_sysctl.c:1398
 register_net_sysctl_sz+0x19e/0x1c0 net/sysctl_net.c:171
 nf_conntrack_standalone_init_sysctl net/netfilter/nf_conntrack_standalone.c:1046 [inline]
 nf_conntrack_pernet_init+0x4bf/0x5d0 net/netfilter/nf_conntrack_standalone.c:1094
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:446
 copy_net_ns+0x31a/0x460 net/core/net_namespace.c:579
 create_new_namespaces+0x1f6/0x420 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x115/0x150 kernel/nsproxy.c:234
 ksys_unshare+0x411/0x760 kernel/fork.c:3268
 __do_sys_unshare kernel/fork.c:3342 [inline]
 __se_sys_unshare kernel/fork.c:3340 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3340
 x64_sys_call+0x1cef/0x3020 arch/x86/include/generated/asm/syscalls_64.h:273
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c179e0 of 8 bytes by task 4508 on cpu 1:
 print_tickdevice+0x144/0x340 kernel/time/timer_list.c:200
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:292
 seq_read_iter+0x5f6/0x8f0 fs/seq_file.c:273
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x47a/0x6b0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 splice_direct_to_actor+0x261/0x680 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7fffffffffffffff -> 0x0000000cc2858b36

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4508 Comm: syz.4.352 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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