syzbot

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

read-write to 0xffff8881034e4388 of 8 bytes by interrupt on cpu 1:
 rtc_handle_legacy_irq drivers/rtc/interface.c:651 [inline]
 rtc_pie_update_irq+0x7b/0xd0 drivers/rtc/interface.c:699
 __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:1041 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 avc_has_perm_noaudit+0x156/0x200 security/selinux/avc.c:1159
 cred_has_capability+0x117/0x280 security/selinux/hooks.c:1659
 selinux_capable+0x31/0x40 security/selinux/hooks.c:2159
 security_capable+0x83/0x90 security/security.c:1181
 ns_capable_common kernel/capability.c:342 [inline]
 ns_capable+0x4d/0xb0 kernel/capability.c:363
 __netlink_ns_capable net/netlink/af_netlink.c:854 [inline]
 netlink_ns_capable net/netlink/af_netlink.c:871 [inline]
 netlink_net_capable+0xaa/0xc0 net/netlink/af_netlink.c:902
 rtnetlink_rcv_msg+0x14c/0x6d0 net/core/rtnetlink.c:6878
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2552
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6978
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:742
 __sys_sendto+0x268/0x330 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2247
 x64_sys_call+0x2d14/0x3000 arch/x86/include/generated/asm/syscalls_64.h:45
 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 0xffff8881034e4388 of 8 bytes by task 6631 on cpu 0:
 rtc_dev_poll+0x78/0xb0 drivers/rtc/dev.c:198
 vfs_poll include/linux/poll.h:82 [inline]
 io_poll_check_events io_uring/poll.c:262 [inline]
 io_poll_task_func+0x17b/0x7c0 io_uring/poll.c:317
 io_handle_tw_list+0xcc/0x1c0 io_uring/io_uring.c:1151
 tctx_task_work_run+0x6d/0x1a0 io_uring/io_uring.c:1216
 tctx_task_work+0x3f/0x80 io_uring/io_uring.c:1234
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 get_signal+0xe12/0xf70 kernel/signal.c:2807
 arch_do_signal_or_restart+0x96/0x440 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x77/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000bfc0 -> 0x000000000000c0c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6631 Comm: syz.3.1120 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================