syzbot

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BUG: KCSAN: data-race in ext4_mark_iloc_dirty / ext4_remount

write to 0xffff888128a07850 of 8 bytes by task 4960 on cpu 1:
 ext4_remount+0x39a/0x16d0 fs/ext4/super.c:5578
 legacy_reconfigure+0x8e/0xa0 fs/fs_context.c:615
 reconfigure_super+0x292/0x4d0 fs/super.c:957
 do_remount fs/namespace.c:2612 [inline]
 path_mount+0x13c2/0x1c70 fs/namespace.c:3184
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3390
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888128a07850 of 8 bytes by task 8728 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:5067 [inline]
 ext4_mark_iloc_dirty+0x11d4/0x1660 fs/ext4/inode.c:5624
 __ext4_mark_inode_dirty+0x448/0x630 fs/ext4/inode.c:5818
 __ext4_ext_dirty fs/ext4/extents.c:169 [inline]
 ext4_ext_remove_space+0x113d/0x14a0 fs/ext4/extents.c:3015
 ext4_ext_truncate+0xf9/0x160 fs/ext4/extents.c:4371
 ext4_truncate+0x889/0xc20 fs/ext4/inode.c:4216
 ext4_evict_inode+0x9cf/0xc20 fs/ext4/inode.c:280
 evict+0x19f/0x470 fs/inode.c:576
 iput_final fs/inode.c:1652 [inline]
 iput+0x44a/0x550 fs/inode.c:1678
 dentry_unlink_inode+0x210/0x220 fs/dcache.c:374
 d_delete+0x78/0xa0 fs/dcache.c:2470
 vfs_rmdir+0x284/0x2a0 fs/namei.c:3726
 do_rmdir+0x16e/0x300 fs/namei.c:3773
 __do_sys_rmdir fs/namei.c:3791 [inline]
 __se_sys_rmdir fs/namei.c:3789 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3789
 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: 8728 Comm: syz-executor.3 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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