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BUG: KCSAN: data-race in __cgroup_account_cputime / cgroup_rstat_flush_locked

write to 0xffffe8ffffc24f68 of 8 bytes by task 7902 on cpu 1:
 cgroup_rstat_cpu_pop_updated kernel/cgroup/rstat.c:139 [inline]
 cgroup_rstat_flush_locked+0x282/0x7f0 kernel/cgroup/rstat.c:161
 cgroup_rstat_flush_hold kernel/cgroup/rstat.c:236 [inline]
 cgroup_base_stat_cputime_show+0x7c/0x310 kernel/cgroup/rstat.c:445
 cpu_stat_show+0xab/0x350 kernel/cgroup/cgroup.c:3562
 cgroup_seqfile_show+0xbe/0x150 kernel/cgroup/cgroup.c:3875
 kernfs_seq_show+0x74/0x80 fs/kernfs/file.c:168
 seq_read_iter+0x2e1/0x930 fs/seq_file.c:230
 kernfs_fop_read_iter+0xd9/0x320 fs/kernfs/file.c:241
 call_read_iter include/linux/fs.h:2108 [inline]
 do_iter_readv_writev+0x2e8/0x360 fs/read_write.c:738
 do_iter_read+0x109/0x4b0 fs/read_write.c:801
 vfs_readv fs/read_write.c:921 [inline]
 do_preadv+0x13b/0x230 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_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffe8ffffc24f68 of 8 bytes by task 7900 on cpu 0:
 cgroup_rstat_updated kernel/cgroup/rstat.c:38 [inline]
 cgroup_base_stat_cputime_account_end kernel/cgroup/rstat.c:363 [inline]
 __cgroup_account_cputime+0x8e/0x1e0 kernel/cgroup/rstat.c:373
 cgroup_account_cputime include/linux/cgroup.h:797 [inline]
 update_curr+0xf4/0x240 kernel/sched/fair.c:821
 dequeue_entity kernel/sched/fair.c:4360 [inline]
 dequeue_task_fair+0xbf/0x8f0 kernel/sched/fair.c:5666
 dequeue_task kernel/sched/core.c:1967 [inline]
 deactivate_task kernel/sched/core.c:1981 [inline]
 __schedule+0x1da/0x670 kernel/sched/core.c:5894
 schedule+0x67/0x90 kernel/sched/core.c:6019
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x162/0x210 kernel/futex.c:2602
 futex_wait+0x143/0x430 kernel/futex.c:2704
 do_futex+0x9c1/0x1f10 kernel/futex.c:3730
 __do_sys_futex kernel/futex.c:3807 [inline]
 __se_sys_futex+0xc6/0x370 kernel/futex.c:3788
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3788
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff88812e746000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7900 Comm: syz-executor.3 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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