[moderation] [kernel?] KCSAN: data-race in clockevents_program_min_delta / print_tickdevice (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 80e54e84911a Linux 6.14-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1672d074580000
kernel config: https://syzkaller.appspot.com/x/.config?x=958433697845b9a6
dashboard link: https://syzkaller.appspot.com/bug?extid=4666e46d6ba0c99ac89e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [anna-...@linutronix.de fred...@kernel.org linux-...@vger.kernel.org tg...@linutronix.de]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e94728c052e3/disk-80e54e84.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742f05e27746/vmlinux-80e54e84.xz
kernel image: https://storage.googleapis.com/syzbot-assets/90d418e775f7/bzImage-80e54e84.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4666e4...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in clockevents_program_min_delta / print_tickdevice

read-write to 0xffff888237d1c240 of 8 bytes by task 5825 on cpu 1:
clockevents_program_min_delta+0xb6/0x260 kernel/time/clockevents.c:246
clockevents_program_event+0x180/0x1f0
tick_program_event+0x7c/0xd0 kernel/time/tick-oneshot.c:44
__hrtimer_reprogram kernel/time/hrtimer.c:697 [inline]
hrtimer_reprogram+0x1cf/0x220 kernel/time/hrtimer.c:880
hrtimer_start_range_ns+0x699/0x720 kernel/time/hrtimer.c:1344
hrtimer_start_expires include/linux/hrtimer.h:274 [inline]
hrtimer_restart include/linux/hrtimer.h:282 [inline]
common_hrtimer_rearm+0xa9/0xc0 kernel/time/posix-timers.c:250
__posixtimer_deliver_signal kernel/time/posix-timers.c:268 [inline]
posixtimer_deliver_signal+0x10c/0x2e0 kernel/time/posix-timers.c:294
dequeue_signal+0x2a5/0x370 kernel/signal.c:659
get_signal+0x376/0x1000 kernel/signal.c:2916
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 0xffff888237d1c240 of 8 bytes by task 5897 on cpu 0:
print_tickdevice+0x2ae/0x340 kernel/time/timer_list.c:234
timer_list_show+0x79/0x180 kernel/time/timer_list.c:300
seq_read_iter+0x2d1/0x930 fs/seq_file.c:230
proc_reg_read_iter+0x118/0x190 fs/proc/inode.c:299
copy_splice_read+0x383/0x5b0 fs/splice.c:365
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x398/0x660 fs/read_write.c:1363
__do_sys_sendfile64 fs/read_write.c:1424 [inline]
__se_sys_sendfile64 fs/read_write.c:1410 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000003d3f7 -> 0x000000000003d3f8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5897 Comm: syz.1.760 Not tainted 6.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

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