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BUG: KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq

read-write to 0xffff888102f5eb80 of 8 bytes by interrupt on cpu 1:
 rtc_handle_legacy_irq drivers/rtc/interface.c:624 [inline]
 rtc_pie_update_irq+0x93/0xf0 drivers/rtc/interface.c:672
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x20c/0x5a0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1d0 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 kcsan_setup_watchpoint+0x415/0x430 kernel/kcsan/core.c:705
 tlb_flush_pte_range include/asm-generic/tlb.h:577 [inline]
 tlb_remove_tlb_entries include/asm-generic/tlb.h:630 [inline]
 zap_present_folio_ptes mm/memory.c:1519 [inline]
 zap_present_ptes mm/memory.c:1586 [inline]
 do_zap_pte_range mm/memory.c:1687 [inline]
 zap_pte_range mm/memory.c:1731 [inline]
 zap_pmd_range mm/memory.c:1823 [inline]
 zap_pud_range mm/memory.c:1852 [inline]
 zap_p4d_range mm/memory.c:1873 [inline]
 unmap_page_range+0xded/0x27b0 mm/memory.c:1894
 unmap_single_vma+0x138/0x1d0 mm/memory.c:1940
 unmap_vmas+0x18a/0x2b0 mm/memory.c:1984
 exit_mmap+0x1b0/0x6c0 mm/mmap.c:1284
 __mmput+0x28/0x1c0 kernel/fork.c:1379
 mmput+0x40/0x50 kernel/fork.c:1401
 exit_mm+0xe4/0x190 kernel/exit.c:589
 do_exit+0x55f/0x17c0 kernel/exit.c:940
 do_group_exit+0xff/0x140 kernel/exit.c:1102
 get_signal+0xe59/0xf70 kernel/signal.c:3034
 arch_do_signal_or_restart+0x97/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x68/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888102f5eb80 of 8 bytes by task 11224 on cpu 0:
 rtc_dev_poll+0x78/0xb0 drivers/rtc/dev.c:198
 vfs_poll include/linux/poll.h:82 [inline]
 __io_arm_poll_handler+0x1eb/0xb70 io_uring/poll.c:583
 io_arm_poll_handler+0x427/0x5b0 io_uring/poll.c:708
 io_queue_async+0x86/0x440 io_uring/io_uring.c:1953
 io_queue_sqe io_uring/io_uring.c:1982 [inline]
 io_req_task_submit+0xbb/0xc0 io_uring/io_uring.c:1375
 io_handle_tw_list+0x18d/0x1c0 io_uring/io_uring.c:1062
 tctx_task_work_run+0x6d/0x1a0 io_uring/io_uring.c:1127
 tctx_task_work+0x3f/0x80 io_uring/io_uring.c:1145
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 get_signal+0xe13/0xf70 kernel/signal.c:2807
 arch_do_signal_or_restart+0x97/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x68/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000011c0 -> 0x00000000000012c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11224 Comm: syz.5.2465 Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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