KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 31f02006 Merge tag 'char-misc-5.10-rc2' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169f4e8a500000
kernel config: https://syzkaller.appspot.com/x/.config?x=1dbf0ab7718f3df5
dashboard link: https://syzkaller.appspot.com/bug?extid=e986a24e133a86ec1dfa
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [fwei...@gmail.com linux-...@vger.kernel.org mi...@kernel.org tg...@linutronix.de]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e986a2...@syzkaller.appspotmail.com

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

read-write to 0xffff88813bd1e2bc of 1 bytes by task 0 on cpu 1:
tick_nohz_idle_enter+0x56/0xa0 kernel/time/tick-sched.c:1032
do_idle+0x36/0x230 kernel/sched/idle.c:248
cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:369
secondary_startup_64_no_verify+0xa6/0xab

read to 0xffff88813bd1e2bc of 1 bytes by task 13384 on cpu 0:
get_cpu_iowait_time_us+0x6b/0x1f0 kernel/time/tick-sched.c:640
get_iowait_time fs/proc/stat.c:69 [inline]
show_stat+0x93e/0xdc0 fs/proc/stat.c:173
seq_read+0x2de/0x890 fs/seq_file.c:208
pde_read fs/proc/inode.c:321 [inline]
proc_reg_read+0xe1/0x1b0 fs/proc/inode.c:331
do_loop_readv_writev fs/read_write.c:761 [inline]
do_iter_read+0x3b1/0x4b0 fs/read_write.c:803
vfs_readv fs/read_write.c:921 [inline]
do_preadv+0x139/0x210 fs/read_write.c:1013
__do_sys_preadv fs/read_write.c:1063 [inline]
__se_sys_preadv fs/read_write.c:1058 [inline]
__x64_sys_preadv+0x54/0x60 fs/read_write.c:1058
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13384 Comm: syz-executor.4 Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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