syzbot

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BUG: KCSAN: data-race in cgroup_finalize_control / mem_cgroup_charge

write to 0xffff88812b78c07c of 4 bytes by task 11068 on cpu 1:
 css_clear_dir kernel/cgroup/cgroup.c:1648 [inline]
 cgroup_apply_control_disable kernel/cgroup/cgroup.c:3110 [inline]
 cgroup_finalize_control+0x7b3/0xb90 kernel/cgroup/cgroup.c:3171
 rebind_subsystems+0x314/0x730 kernel/cgroup/cgroup.c:1743
 cgroup_destroy_root+0x7e/0x410 kernel/cgroup/cgroup.c:1320
 css_free_rwork_fn+0x251/0x390 kernel/cgroup/cgroup.c:4972
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88812b78c07c of 4 bytes by task 25154 on cpu 0:
 css_put include/linux/cgroup.h:403 [inline]
 mem_cgroup_charge+0x25f/0x490 mm/memcontrol.c:6727
 __add_to_page_cache_locked+0x4d5/0x6e0 mm/filemap.c:849
 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:919
 pagecache_get_page+0x554/0x900 mm/filemap.c:1721
 grab_cache_page_write_begin+0x3f/0x70 mm/filemap.c:3347
 ext4_da_write_begin+0x33c/0xa30 fs/ext4/inode.c:2966
 generic_perform_write+0x196/0x390 mm/filemap.c:3397
 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:270
 ext4_file_write_iter+0x57b/0x1000 fs/ext4/file.c:498
 call_write_iter include/linux/fs.h:1872 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x665/0x6f0 fs/read_write.c:578
 ksys_write+0xce/0x180 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 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: 25154 Comm: syz-executor.0 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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