[moderation] [kernel?] KCSAN: data-race in clockevents_program_event / print_tickdevice (13)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9448598b22c5 Linux 6.19-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d52e2a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca
dashboard link: https://syzkaller.appspot.com/bug?extid=6c4f83ab248e1807a405
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
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/1ef99b8b9053/disk-9448598b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2931849da3dd/vmlinux-9448598b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ff3bf390daa9/bzImage-9448598b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6c4f83...@syzkaller.appspotmail.com

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

write to 0xffff888237c17b58 of 8 bytes by task 15527 on cpu 0:
clockevents_program_event+0x3e/0x4c0 kernel/time/clockevents.c:313
tick_program_event+0x79/0xc0 kernel/time/tick-oneshot.c:48
__hrtimer_reprogram kernel/time/hrtimer.c:678 [inline]
hrtimer_reprogram+0x1d4/0x220 kernel/time/hrtimer.c:861
hrtimer_start_range_ns+0x6b1/0x740 kernel/time/hrtimer.c:1323
hrtimer_start_expires include/linux/hrtimer.h:273 [inline]
hrtimer_sleeper_start_expires kernel/time/hrtimer.c:2039 [inline]
do_nanosleep+0x79/0x330 kernel/time/hrtimer.c:2113
hrtimer_nanosleep+0x1b8/0x360 kernel/time/hrtimer.c:2163
common_nsleep+0x62/0x80 kernel/time/posix-timers.c:1352
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
__se_sys_clock_nanosleep+0x21a/0x250 kernel/time/posix-timers.c:1375
__x64_sys_clock_nanosleep+0x55/0x70 kernel/time/posix-timers.c:1375
x64_sys_call+0x2734/0x3000 arch/x86/include/generated/asm/syscalls_64.h:231
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c17b58 of 8 bytes by task 15546 on cpu 1:
print_tickdevice+0x142/0x340 kernel/time/timer_list.c:206
timer_list_show+0x6c/0x170 kernel/time/timer_list.c:298
seq_read_iter+0x636/0x950 fs/seq_file.c:272
proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
copy_splice_read+0x442/0x660 fs/splice.c:363
do_splice_read fs/splice.c:982 [inline]
splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
do_splice_direct_actor fs/splice.c:1204 [inline]
do_splice_direct+0xda/0x150 fs/splice.c:1230
do_sendfile+0x380/0x650 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1431 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000056df16c980 -> 0x00000056df1330e0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15546 Comm: syz.5.2744 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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