syzbot

==================================================================
BUG: KCSAN: data-race in iput / writeback_sb_inodes

write to 0xffff8880b8d885c0 of 8 bytes by task 3793 on cpu 0:
 writeback_sb_inodes+0x3bd/0xa10 fs/fs-writeback.c:1705
 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

read to 0xffff8880b8d885c0 of 8 bytes by task 9049 on cpu 1:
 iput+0x4d/0x4d0 fs/inode.c:1588
 dentry_unlink_inode+0x272/0x2e0 fs/dcache.c:374
 d_delete fs/dcache.c:2451 [inline]
 d_delete+0xca/0xe0 fs/dcache.c:2440
 vfs_rmdir fs/namei.c:3702 [inline]
 vfs_rmdir+0x2f1/0x310 fs/namei.c:3667
 do_rmdir+0x2e9/0x320 fs/namei.c:3750
 __do_sys_rmdir fs/namei.c:3768 [inline]
 __se_sys_rmdir fs/namei.c:3766 [inline]
 __x64_sys_rmdir+0x2c/0x40 fs/namei.c:3766
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9049 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================