syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_sb_inodes

write to 0xffff8881360b6820 of 8 bytes by task 1836 on cpu 0:
 writeback_sb_inodes+0x481/0xdf0 fs/fs-writeback.c:1880
 wb_writeback+0x26b/0x650 fs/fs-writeback.c:2064
 wb_do_writeback+0x101/0x560 fs/fs-writeback.c:2207
 wb_workfn+0xc8/0x440 fs/fs-writeback.c:2248
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

read to 0xffff8881360b6820 of 8 bytes by task 7480 on cpu 1:
 __mark_inode_dirty+0xd7/0x6c0 fs/fs-writeback.c:2430
 ext4_mb_new_blocks+0xafd/0x1520
 ext4_ext_map_blocks+0x1107/0x1940 fs/ext4/extents.c:4282
 ext4_map_blocks+0x55e/0xb90 fs/ext4/inode.c:638
 ext4_alloc_file_blocks+0x1be/0x570 fs/ext4/extents.c:4467
 ext4_fallocate+0x24c/0x470 fs/ext4/extents.c:4744
 vfs_fallocate+0x486/0x720 fs/open.c:308
 do_vfs_ioctl+0x13cb/0x14a0 fs/ioctl.c:853
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000020007 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7480 Comm: syz-executor.4 Not tainted 5.17.0-rc4-syzkaller-00241-g7f25f0412c9e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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