[moderation] [kernel?] KCSAN: data-race in print_cpu / tick_nohz_idle_enter (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fca7526b7d89 drm/tests/drm_buddy: fix build failure on 32-..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=130ac4b4180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7507056e4ee79a
dashboard link: https://syzkaller.appspot.com/bug?extid=e19f5c95e492efe7c2ea
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/c63152c2a9c6/disk-fca7526b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6f039180eecf/vmlinux-fca7526b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0340d7a9d91f/bzImage-fca7526b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e19f5c...@syzkaller.appspotmail.com

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

write to 0xffff888237d1f668 of 8 bytes by task 0 on cpu 1:
tick_nohz_start_idle kernel/time/tick-sched.c:687 [inline]
tick_nohz_idle_enter+0x85/0xd0 kernel/time/tick-sched.c:1175
do_idle+0x3c/0x230 kernel/sched/idle.c:256
cpu_startup_entry+0x24/0x30 kernel/sched/idle.c:410
start_secondary+0x82/0x90 arch/x86/kernel/smpboot.c:336
secondary_startup_64_no_verify+0x15f/0x16b

read to 0xffff888237d1f668 of 8 bytes by task 31776 on cpu 0:
print_cpu+0x4c4/0x640 kernel/time/timer_list.c:158
timer_list_show+0x115/0x180 kernel/time/timer_list.c:291
seq_read_iter+0x612/0x8f0 fs/seq_file.c:272
proc_reg_read_iter+0x114/0x180 fs/proc/inode.c:302
call_read_iter include/linux/fs.h:2079 [inline]
copy_splice_read+0x39f/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x268/0x660 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x960 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_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000008c29236342 -> 0x0000008c2925a868

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 31776 Comm: syz-executor.1 Not tainted 6.8.0-rc5-syzkaller-00002-gfca7526b7d89 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

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