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BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick

read-write to 0xffff888100a42cb8 of 8 bytes by interrupt on cpu 0:
 wq_worker_tick+0x60/0x230 kernel/workqueue.c:1474
 sched_tick+0xd7/0x220 kernel/sched/core.c:5546
 update_process_times+0x15f/0x190 kernel/time/timer.c:2479
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x276/0x3d0 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x20f/0x5a0 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 check_access kernel/kcsan/core.c:957 [inline]
 __kcsan_check_access+0x8/0x1e0 kernel/kcsan/core.c:958
 instrument_read_write include/linux/instrumented.h:55 [inline]
 atomic_try_cmpxchg include/linux/atomic/atomic-instrumented.h:1279 [inline]
 static_key_dec_not_one kernel/jump_label.c:287 [inline]
 __static_key_slow_dec_cpuslocked+0x8b/0x1e0 kernel/jump_label.c:297
 __static_key_slow_dec kernel/jump_label.c:321 [inline]
 static_key_slow_dec+0x34/0x60 kernel/jump_label.c:336
 io_ring_ctx_free+0x26d/0x3d0 io_uring/io_uring.c:2866
 io_ring_exit_work+0x4ef/0x520 io_uring/io_uring.c:3073
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read-write to 0xffff888100a42cb8 of 8 bytes by interrupt on cpu 1:
 wq_worker_tick+0x60/0x230 kernel/workqueue.c:1474
 sched_tick+0xd7/0x220 kernel/sched/core.c:5546
 update_process_times+0x15f/0x190 kernel/time/timer.c:2479
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x276/0x3d0 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x20f/0x5a0 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056
 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+0x2c/0x190 kernel/kcsan/core.c:1025
 slab_pgdat mm/slab.h:173 [inline]
 __memcg_slab_free_hook+0x170/0x230 mm/memcontrol.c:3240
 memcg_slab_free_hook mm/slub.c:2364 [inline]
 slab_free mm/slub.c:6665 [inline]
 kfree+0x2b9/0x3c0 mm/slub.c:6876
 io_free_region+0xa3/0x150 io_uring/memmap.c:104
 io_rings_free io_uring/io_uring.c:2756 [inline]
 io_ring_ctx_free+0x202/0x3d0 io_uring/io_uring.c:2863
 io_ring_exit_work+0x4ef/0x520 io_uring/io_uring.c:3073
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x00000000000a8750 -> 0x00000000000aae60

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2919 Comm: kworker/u8:16 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: iou_exit io_ring_exit_work
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