==================================================================
BUG: KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq

read-write to 0xffff8881027ff380 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+0x20f/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:1039 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1d0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 __tsan_read8+0x12/0x190 kernel/kcsan/core.c:1025
 pud_pgtable arch/x86/include/asm/pgtable.h:1103 [inline]
 pmd_offset include/linux/pgtable.h:146 [inline]
 change_pmd_range mm/mprotect.c:362 [inline]
 change_pud_range mm/mprotect.c:472 [inline]
 change_p4d_range mm/mprotect.c:498 [inline]
 change_protection_range mm/mprotect.c:526 [inline]
 change_protection+0x79b/0x15f0 mm/mprotect.c:560
 mprotect_fixup+0x41a/0x570 mm/mprotect.c:676
 do_mprotect_pkey+0x6d6/0x980 mm/mprotect.c:832
 __do_sys_mprotect mm/mprotect.c:853 [inline]
 __se_sys_mprotect mm/mprotect.c:850 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:850
 x64_sys_call+0x2794/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881027ff380 of 8 bytes by task 8003 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+0x427/0x590 io_uring/poll.c:708
 io_queue_async+0x60/0x3a0 io_uring/io_uring.c:1949
 io_queue_sqe io_uring/io_uring.c:1975 [inline]
 io_req_task_submit+0xbb/0xc0 io_uring/io_uring.c:1380
 io_handle_tw_list+0x18d/0x1c0 io_uring/io_uring.c:1067
 tctx_task_work_run+0x6d/0x1a0 io_uring/io_uring.c:1132
 tctx_task_work+0x3f/0x80 io_uring/io_uring.c:1150
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 get_signal+0xe13/0xf70 kernel/signal.c:2807
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x7a/0x100 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000a1c0 -> 0x000000000000a2c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8003 Comm: syz.0.1516 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================