[moderation] [kernel?] KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 05f7e89ab973 Linux 6.19
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1194f65a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e27f4588a0f2183
dashboard link: https://syzkaller.appspot.com/bug?extid=fe1058f12ef7ca496af9
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [anna-...@linutronix.de fred...@kernel.org linux-...@vger.kernel.org tg...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bb848ac8f95b/disk-05f7e89a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aae899d0a2ce/vmlinux-05f7e89a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e8b66ec5250e/bzImage-05f7e89a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe1058...@syzkaller.appspotmail.com

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

write to 0xffff888237d17b58 of 8 bytes by interrupt on cpu 1:
hrtimer_interrupt+0x84/0x810 kernel/time/hrtimer.c:1882
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
lru_gen_inc_refs mm/swap.c:391 [inline]
folio_mark_accessed+0x6f/0x3a0 mm/swap.c:460
follow_page_pte+0x572/0x6e0 mm/gup.c:886
follow_pmd_mask mm/gup.c:915 [inline]
follow_pud_mask mm/gup.c:967 [inline]
follow_p4d_mask mm/gup.c:984 [inline]
follow_page_mask mm/gup.c:1023 [inline]
__get_user_pages+0x756/0x1ea0 mm/gup.c:1426
__get_user_pages_locked mm/gup.c:1692 [inline]
faultin_page_range+0x107/0x4d0 mm/gup.c:1912
madvise_populate mm/madvise.c:976 [inline]
madvise_do_behavior+0x19f/0xa10 mm/madvise.c:1935
do_madvise+0x10e/0x190 mm/madvise.c:2030
__do_sys_madvise mm/madvise.c:2039 [inline]
__se_sys_madvise mm/madvise.c:2037 [inline]
__x64_sys_madvise+0x63/0x80 mm/madvise.c:2037
x64_sys_call+0x1c6b/0x3000 arch/x86/include/generated/asm/syscalls_64.h:29
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d17b58 of 8 bytes by task 5743 on cpu 0:
print_tickdevice+0x142/0x340 kernel/time/timer_list.c:206
timer_list_show+0x6c/0x170 kernel/time/timer_list.c:298
seq_read_iter+0x636/0x940 fs/seq_file.c:272
proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
copy_splice_read+0x471/0x6c0 fs/splice.c:363
do_splice_read fs/splice.c:982 [inline]
splice_direct_to_actor+0x26e/0x670 fs/splice.c:1086
do_splice_direct_actor fs/splice.c:1204 [inline]
do_splice_direct+0x119/0x1a0 fs/splice.c:1230
do_sendfile+0x382/0x650 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+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000129f80e76b -> 0x000000129f81f8db

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5743 Comm: syz.2.615 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
==================================================================


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