==================================================================
BUG: KCSAN: data-race in __perf_event_read_value / event_sched_in

write to 0xffff888120800530 of 8 bytes by task 23628 on cpu 0:
 __perf_update_times kernel/events/core.c:-1 [inline]
 perf_event_update_time kernel/events/core.c:762 [inline]
 perf_event_set_state kernel/events/core.c:781 [inline]
 event_sched_in+0x2f0/0xca0 kernel/events/core.c:2822
 group_sched_in kernel/events/core.c:2869 [inline]
 merge_sched_in+0x252/0xbb0 kernel/events/core.c:4128
 visit_groups_merge+0x9db/0xfd0 kernel/events/core.c:4059
 pmu_groups_sched_in kernel/events/core.c:4164 [inline]
 __pmu_ctx_sched_in kernel/events/core.c:-1 [inline]
 ctx_sched_in+0x3ba/0x410 kernel/events/core.c:4243
 perf_event_sched_in kernel/events/core.c:-1 [inline]
 perf_event_context_sched_in kernel/events/core.c:4290 [inline]
 __perf_event_task_sched_in+0x678/0xad0 kernel/events/core.c:4319
 perf_event_task_sched_in include/linux/perf_event.h:1639 [inline]
 finish_task_switch+0x1f8/0x280 kernel/sched/core.c:5150
 context_switch kernel/sched/core.c:5301 [inline]
 __schedule+0x93c/0xd40 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x5e/0xd0 kernel/sched/core.c:7008
 futex_do_wait kernel/futex/waitwake.c:358 [inline]
 __futex_wait+0x121/0x260 kernel/futex/waitwake.c:687
 futex_wait+0x9c/0x1d0 kernel/futex/waitwake.c:715
 do_futex+0x2bf/0x380 kernel/futex/syscalls.c:130
 __do_sys_futex kernel/futex/syscalls.c:207 [inline]
 __se_sys_futex+0x2f6/0x370 kernel/futex/syscalls.c:188
 __x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:188
 x64_sys_call+0x24ab/0x3020 arch/x86/include/generated/asm/syscalls_64.h:203
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888120800530 of 8 bytes by task 23676 on cpu 1:
 __perf_event_read_value+0x82/0x1d0 kernel/events/core.c:6047
 perf_read_one kernel/events/core.c:6204 [inline]
 __perf_read kernel/events/core.c:6257 [inline]
 perf_read+0x2d6/0x670 kernel/events/core.c:6274
 loop_rw_iter+0x2c8/0x400 include/linux/uio.h:-1
 io_iter_do_read io_uring/rw.c:837 [inline]
 __io_read+0xbf6/0xc50 io_uring/rw.c:951
 io_read+0x4a/0x190 io_uring/rw.c:1031
 __io_issue_sqe+0xfd/0x2d0 io_uring/io_uring.c:1384
 io_issue_sqe+0x206/0xc00 io_uring/io_uring.c:1407
 io_wq_submit_work+0x5bc/0x830 io_uring/io_uring.c:1519
 io_worker_handle_work+0x41e/0x950 io_uring/io-wq.c:652
 io_wq_worker+0x23d/0x970 io_uring/io-wq.c:706
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000041cab82f -> 0x0000000041cb3dfe

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 23676 Comm: iou-wrk-23628 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================