[moderation] [rtc?] KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cdd30ebb1b9f module: Convert symbol namespace to string li..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1283afc0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5337d87dae437af8
dashboard link: https://syzkaller.appspot.com/bug?extid=7623b588d2f48190bb96
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [alexandr...@bootlin.com linux-...@vger.kernel.org linu...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eaeb17b3983b/disk-cdd30ebb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/813f9ca32e21/vmlinux-cdd30ebb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8002dbda52bd/bzImage-cdd30ebb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7623b5...@syzkaller.appspotmail.com

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

read-write to 0xffff888102f63b80 of 8 bytes by interrupt on cpu 1:
rtc_handle_legacy_irq drivers/rtc/interface.c:624 [inline]
rtc_pie_update_irq+0x95/0xf0 drivers/rtc/interface.c:672
__run_hrtimer kernel/time/hrtimer.c:1739 [inline]
__hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1803
hrtimer_interrupt+0x235/0x4a0 kernel/time/hrtimer.c:1865
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+0x6e/0x80 arch/x86/kernel/apic/apic.c:1049
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
free_swap_cache mm/swap_state.c:294 [inline]
free_pages_and_swap_cache+0x204/0x410 mm/swap_state.c:325
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
tlb_flush_mmu+0x2cf/0x440 mm/mmu_gather.c:373
zap_pte_range mm/memory.c:1714 [inline]
zap_pmd_range mm/memory.c:1753 [inline]
zap_pud_range mm/memory.c:1782 [inline]
zap_p4d_range mm/memory.c:1803 [inline]
unmap_page_range+0x1fc8/0x2380 mm/memory.c:1824
unmap_single_vma+0x142/0x1d0 mm/memory.c:1870
unmap_vmas+0x18d/0x2b0 mm/memory.c:1914
exit_mmap+0x18a/0x680 mm/mmap.c:1667
__mmput+0x28/0x1d0 kernel/fork.c:1353
mmput+0x4c/0x60 kernel/fork.c:1375
exit_mm+0xe4/0x190 kernel/exit.c:570
do_exit+0x55e/0x17f0 kernel/exit.c:925
do_group_exit+0x102/0x150 kernel/exit.c:1087
get_signal+0xeb9/0x1000 kernel/signal.c:3017
arch_do_signal_or_restart+0x95/0x4b0 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+0x62/0x120 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888102f63b80 of 8 bytes by task 9876 on cpu 0:
rtc_dev_poll+0x76/0xb0 drivers/rtc/dev.c:198
vfs_poll include/linux/poll.h:84 [inline]
__io_arm_poll_handler+0x1e5/0xd50 io_uring/poll.c:578
io_arm_poll_handler+0x3f6/0x5b0 io_uring/poll.c:706
io_queue_async+0x89/0x320 io_uring/io_uring.c:1924
io_queue_sqe io_uring/io_uring.c:1953 [inline]
io_req_task_submit+0xb9/0xc0 io_uring/io_uring.c:1370
io_handle_tw_list+0x1b9/0x200 io_uring/io_uring.c:1053
tctx_task_work_run+0x6e/0x1c0 io_uring/io_uring.c:1117
tctx_task_work+0x40/0x80 io_uring/io_uring.c:1135
task_work_run+0x13a/0x1a0 kernel/task_work.c:239
get_signal+0xe78/0x1000 kernel/signal.c:2790
arch_do_signal_or_restart+0x95/0x4b0 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+0x62/0x120 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000ddc0 -> 0x000000000000dec0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9876 Comm: syz.4.1270 Tainted: G W 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.