[moderation] [kernel?] KCSAN: data-race in print_cpu / tick_nohz_idle_enter (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8d025e2092e2 Merge tag 'erofs-for-6.9-rc2-fixes' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11edf265180000
kernel config: https://syzkaller.appspot.com/x/.config?x=aa27611f143168c9
dashboard link: https://syzkaller.appspot.com/bug?extid=0152ac61fac5c14c46d0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [fred...@kernel.org linux-...@vger.kernel.org mi...@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/25a7994bce97/disk-8d025e20.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd186f3a786f/vmlinux-8d025e20.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a958ca120141/bzImage-8d025e20.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0152ac...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in print_cpu / tick_nohz_idle_enter

read-write to 0xffff888237d204f8 of 8 bytes by task 0 on cpu 1:
tick_sched_flag_set kernel/time/tick-sched.c:193 [inline]
tick_nohz_idle_enter+0x59/0xe0 kernel/time/tick-sched.c:1253
do_idle+0x3d/0x230 kernel/sched/idle.c:277
cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:430
start_secondary+0x94/0xa0 arch/x86/kernel/smpboot.c:313
common_startup_64+0x12c/0x137

read to 0xffff888237d204f8 of 8 bytes by task 16016 on cpu 0:
print_cpu+0x404/0x670 kernel/time/timer_list.c:156
timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
seq_read_iter+0x2d7/0x940 fs/seq_file.c:230
proc_reg_read_iter+0x11e/0x190 fs/proc/inode.c:299
call_read_iter include/linux/fs.h:2102 [inline]
copy_splice_read+0x3a4/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/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+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_64+0xd3/0x1d0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x0000000000000030 -> 0x0000000000000035

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16016 Comm: syz-executor.4 Not tainted 6.9.0-rc1-syzkaller-00061-g8d025e2092e2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================


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