syzbot

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BUG: KCSAN: data-race in __writeback_single_inode / iput

write to 0xffff8880bb44bc00 of 8 bytes by task 7130 on cpu 1:
 iput_final fs/inode.c:1567 [inline]
 iput+0x2e6/0x4d0 fs/inode.c:1598
 do_unlinkat+0x388/0x550 fs/namei.c:3879
 __do_sys_unlink fs/namei.c:3920 [inline]
 __se_sys_unlink fs/namei.c:3918 [inline]
 __x64_sys_unlink+0x38/0x50 fs/namei.c:3918
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880bb44bc00 of 8 bytes by task 29 on cpu 0:
 __writeback_single_inode+0x60/0x910 fs/fs-writeback.c:1448
 writeback_sb_inodes+0x4c8/0xa10 fs/fs-writeback.c:1716
 wb_writeback+0x1f9/0x6a0 fs/fs-writeback.c:1892
 wb_do_writeback fs/fs-writeback.c:2037 [inline]
 wb_workfn+0x215/0x970 fs/fs-writeback.c:2078
 process_one_work+0x424/0x930 kernel/workqueue.c:2268
 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2414
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29 Comm: kworker/u4:2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
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