==================================================================
BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick

read-write to 0xffff8881000c62d8 of 8 bytes by interrupt on cpu 0:
 wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508
 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5678
 update_process_times+0x15e/0x190 kernel/time/timer.c:2480
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x275/0x3d0 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 ipcns_get+0x2d/0x110 ipc/namespace.c:220
 ns_get_path_task fs/nsfs.c:88 [inline]
 ns_get_path_cb fs/nsfs.c:72 [inline]
 ns_get_path+0x2d/0x80 fs/nsfs.c:99
 perf_fill_ns_link_info kernel/events/core.c:9412 [inline]
 perf_event_namespaces+0x44a/0x6f0 kernel/events/core.c:9462
 perf_event_fork+0x117/0x420 kernel/events/core.c:9246
 copy_process+0x2326/0x2370 kernel/fork.c:2526
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2721
 user_mode_thread+0x9c/0xd0 kernel/fork.c:2797
 call_usermodehelper_exec_work+0x41/0x160 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff8881000c62d8 of 8 bytes by interrupt on cpu 1:
 wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508
 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5678
 update_process_times+0x15e/0x190 kernel/time/timer.c:2480
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x275/0x3d0 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 preempt_count arch/x86/include/asm/preempt.h:27 [inline]
 get_ctx kernel/kcsan/core.c:206 [inline]
 check_access kernel/kcsan/core.c:750 [inline]
 __tsan_unaligned_write8+0xf3/0x180 kernel/kcsan/core.c:1025
 set_normalized_timespec64+0xd4/0x110 kernel/time/time.c:507
 inode_set_ctime_to_ts fs/inode.c:2770 [inline]
 inode_set_ctime_current+0x227/0x8c0 fs/inode.c:2835
 simple_inode_init_ts fs/libfs.c:2124 [inline]
 prepare_anon_dentry fs/libfs.c:2164 [inline]
 path_from_stashed+0x12d/0x330 fs/libfs.c:2243
 ns_get_path_cb fs/nsfs.c:76 [inline]
 ns_get_path+0x62/0x80 fs/nsfs.c:99
 perf_fill_ns_link_info kernel/events/core.c:9412 [inline]
 perf_event_namespaces+0x1db/0x6f0 kernel/events/core.c:9450
 perf_event_fork+0x117/0x420 kernel/events/core.c:9246
 copy_process+0x2326/0x2370 kernel/fork.c:2526
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2721
 user_mode_thread+0x9c/0xd0 kernel/fork.c:2797
 call_usermodehelper_exec_work+0x41/0x160 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000000ef420 -> 0x00000000000f1b30

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6334 Comm: kworker/u8:15 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================