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

write to 0xffff88806ddb55c8 of 8 bytes by task 21 on cpu 1:
 writeback_sb_inodes+0x427/0xff0 fs/fs-writeback.c:1190
 wb_writeback+0x28d/0x6f0 fs/fs-writeback.c:1894
 wb_do_writeback+0x101/0x5f0 fs/fs-writeback.c:2039
 wb_workfn+0xc8/0x470 fs/fs-writeback.c:2080
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88806ddb55c8 of 8 bytes by task 8728 on cpu 0:
 evict+0x42/0x470 fs/inode.c:559
 iput_final fs/inode.c:1652 [inline]
 iput+0x44a/0x550 fs/inode.c:1678
 do_unlinkat+0x2c9/0x4d0 fs/namei.c:3902
 __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: 0 PID: 8728 Comm: syz-executor.4 Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================