syzbot

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BUG: KCSAN: data-race in hrtimer_reprogram / print_cpu

write to 0xffff888237c1ae20 of 8 bytes by task 8195 on cpu 0:
 __hrtimer_reprogram kernel/time/hrtimer.c:665 [inline]
 hrtimer_reprogram+0x1a2/0x220 kernel/time/hrtimer.c:870
 hrtimer_start_range_ns+0x6a2/0x730 kernel/time/hrtimer.c:1334
 hrtimer_start include/linux/hrtimer.h:265 [inline]
 perf_swevent_start_hrtimer kernel/events/core.c:11659 [inline]
 cpu_clock_event_start kernel/events/core.c:11716 [inline]
 cpu_clock_event_add+0x10e/0x130 kernel/events/core.c:11728
 event_sched_in+0x4a8/0x710 kernel/events/core.c:2663
 group_sched_in kernel/events/core.c:2696 [inline]
 merge_sched_in kernel/events/core.c:3930 [inline]
 visit_groups_merge+0xc10/0x1d10 kernel/events/core.c:3875
 pmu_groups_sched_in kernel/events/core.c:3961 [inline]
 __pmu_ctx_sched_in+0xcd/0xf0 kernel/events/core.c:3973
 ctx_sched_in+0x361/0x3b0 kernel/events/core.c:4024
 perf_event_sched_in kernel/events/core.c:2794 [inline]
 perf_event_context_sched_in kernel/events/core.c:4071 [inline]
 __perf_event_task_sched_in+0x59e/0xa80 kernel/events/core.c:4100
 perf_event_task_sched_in include/linux/perf_event.h:1573 [inline]
 finish_task_switch+0x218/0x2b0 kernel/sched/core.c:5235
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x82d/0xae0 kernel/sched/core.c:6747
 __schedule_loop kernel/sched/core.c:6824 [inline]
 schedule+0x5f/0xd0 kernel/sched/core.c:6839
 exit_to_user_mode_loop kernel/entry/common.c:102 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x42/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c1ae20 of 8 bytes by task 8184 on cpu 1:
 print_cpu+0x307/0x680 kernel/time/timer_list.c:133
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x661/0x970 fs/seq_file.c:272
 proc_reg_read_iter+0x118/0x190 fs/proc/inode.c:299
 copy_splice_read+0x390/0x5d0 fs/splice.c:363
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xd9/0x150 fs/splice.c:1227
 do_sendfile+0x40a/0x690 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
 x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000247ebfffa5 -> 0x7fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8184 Comm: syz.4.1703 Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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