syzbot

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BUG: KCSAN: data-race in get_cpu_iowait_time_us / tick_nohz_idle_enter

read-write to 0xffff888237d1e1fc of 1 bytes by task 0 on cpu 1:
 tick_nohz_idle_enter+0x6c/0xc0 kernel/time/tick-sched.c:1159
 do_idle+0x3d/0x250 kernel/sched/idle.c:277
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 start_secondary+0x78/0x80 arch/x86/kernel/smpboot.c:264
 secondary_startup_64_no_verify+0xcf/0xdb

read to 0xffff888237d1e1fc of 1 bytes by task 7253 on cpu 0:
 get_cpu_iowait_time_us+0x68/0x1d0
 get_iowait_time fs/proc/stat.c:70 [inline]
 show_stat+0x1af/0xcd0 fs/proc/stat.c:135
 seq_read_iter+0x2c3/0x8e0 fs/seq_file.c:230
 proc_reg_read_iter+0xd4/0x170 fs/proc/inode.c:301
 call_read_iter include/linux/fs.h:2180 [inline]
 generic_file_splice_read+0xde/0x2b0 fs/splice.c:309
 do_splice_to fs/splice.c:793 [inline]
 splice_direct_to_actor+0x26c/0x620 fs/splice.c:865
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x08 -> 0x0d

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7253 Comm: syz-executor.0 Not tainted 6.1.0-syzkaller-10971-g041fae9c105a-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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