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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 521b619a Merge tag 'linux-kselftest-kunit-fixes-5.10-rc3' ..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1581438e500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=e6d5592a6e19e81e8946
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+e6d559...@syzkaller.appspotmail.com

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

write to 0xffff88813bd1e308 of 8 bytes by task 0 on cpu 1:
update_ts_time_stats kernel/time/tick-sched.c:550 [inline]
tick_nohz_stop_idle kernel/time/tick-sched.c:564 [inline]
tick_nohz_irq_enter kernel/time/tick-sched.c:1284 [inline]
tick_irq_enter+0x102/0x1c0 kernel/time/tick-sched.c:1303
irq_enter_rcu+0x2e/0x60 kernel/softirq.c:359
sysvec_apic_timer_interrupt+0x11/0x90 arch/x86/kernel/apic/apic.c:1091
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
acpi_idle_do_entry drivers/acpi/processor_idle.c:517 [inline]
acpi_idle_enter+0x25b/0x2e0 drivers/acpi/processor_idle.c:648
cpuidle_enter_state+0x2bd/0x750 drivers/cpuidle/cpuidle.c:237
cpuidle_enter+0x3c/0x60 drivers/cpuidle/cpuidle.c:351
call_cpuidle kernel/sched/idle.c:132 [inline]
cpuidle_idle_call kernel/sched/idle.c:213 [inline]
do_idle+0x193/0x230 kernel/sched/idle.c:273
cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:369
secondary_startup_64_no_verify+0xb0/0xbb

read to 0xffff88813bd1e308 of 8 bytes by task 5478 on cpu 0:
get_cpu_iowait_time_us+0x1da/0x1f0 kernel/time/tick-sched.c:648
get_iowait_time fs/proc/stat.c:69 [inline]
show_stat+0x2df/0xdc0 fs/proc/stat.c:132
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: 5478 Comm: syz-executor.3 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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