syzbot

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BUG: KCSAN: data-race in ext4_remount / inode_needs_sync

write to 0xffff888217e07050 of 8 bytes by task 20896 on cpu 0:
 ext4_remount+0x10a8/0x16d0 fs/ext4/super.c:5804
 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 0xffff888217e07050 of 8 bytes by task 8716 on cpu 1:
 inode_needs_sync+0x22/0xe0 fs/inode.c:2019
 __ext4_handle_dirty_metadata+0x1b7/0x5a0 fs/ext4/ext4_jbd2.c:363
 ext4_handle_dirty_dirblock+0x184/0x330 fs/ext4/namei.c:411
 ext4_delete_entry+0x23a/0x340 fs/ext4/namei.c:2535
 ext4_unlink+0x5aa/0x9e0 fs/ext4/namei.c:3236
 vfs_unlink+0x232/0x3c0 fs/namei.c:3832
 do_unlinkat+0x28a/0x4d0 fs/namei.c:3896
 __do_sys_unlink fs/namei.c:3942 [inline]
 __se_sys_unlink fs/namei.c:3940 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3940
 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: 1 PID: 8716 Comm: syz-executor.5 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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