[moderation] [kernel?] KCSAN: data-race in clockevents_program_event / print_tickdevice (12)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d7b8f8e20813 Linux 6.16-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167f928c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ce48b74bcedce10f
dashboard link: https://syzkaller.appspot.com/bug?extid=0a9e9ee5e8f45fd819a9
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
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/6a4c012a3b93/disk-d7b8f8e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e3a6050563a6/vmlinux-d7b8f8e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2bdc7eedebcd/bzImage-d7b8f8e2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0a9e9e...@syzkaller.appspotmail.com

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

write to 0xffff888237d17758 of 8 bytes by interrupt on cpu 1:
clockevents_program_event+0x3f/0x4e0 kernel/time/clockevents.c:313
tick_program_event+0x79/0xc0 kernel/time/tick-oneshot.c:44
hrtimer_interrupt+0x25e/0x460 kernel/time/hrtimer.c:1900
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
kcsan_setup_watchpoint+0x415/0x430 kernel/kcsan/core.c:705
skb_is_nonlinear include/linux/skbuff.h:2481 [inline]
skb_tailroom include/linux/skbuff.h:2852 [inline]
audit_log_n_string+0x4d/0x290 kernel/audit.c:2072
audit_log_n_untrustedstring kernel/audit.c:2123 [inline]
audit_log_untrustedstring+0xb6/0xd0 kernel/audit.c:2136
dump_common_audit_data security/lsm_audit.c:420 [inline]
common_lsm_audit+0x192/0x230 security/lsm_audit.c:451
slow_avc_audit+0x104/0x140 security/selinux/avc.c:779
avc_audit security/selinux/include/avc.h:127 [inline]
avc_has_perm+0x128/0x150 security/selinux/avc.c:1198
selinux_bpf+0xa3/0xc0 security/selinux/hooks.c:-1
security_bpf+0x52/0x90 security/security.c:5640
__sys_bpf+0x1bf/0x790 kernel/bpf/syscall.c:5812
__do_sys_bpf kernel/bpf/syscall.c:5943 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5941 [inline]
__x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:5941
x64_sys_call+0x2478/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:322
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 0xffff888237d17758 of 8 bytes by task 3002 on cpu 0:
print_tickdevice+0x142/0x340 kernel/time/timer_list.c:208
timer_list_show+0x6c/0x170 kernel/time/timer_list.c:300
seq_read_iter+0x627/0x940 fs/seq_file.c:272
proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
copy_splice_read+0x3c1/0x5f0 fs/splice.c:363
do_splice_read fs/splice.c:979 [inline]
splice_direct_to_actor+0x26c/0x680 fs/splice.c:1083
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xda/0x150 fs/splice.c:1227
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+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
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

value changed: 0x7fffffffffffffff -> 0x0000006d26fa87e8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3002 Comm: GPL Not tainted 6.16.0-rc5-syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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[syzbot]

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