syzbot

==================================================================
BUG: KCSAN: data-race in __ext4_update_other_inode_time / writeback_sb_inodes

write to 0xffff888106420258 of 8 bytes by task 127 on cpu 0:
 writeback_sb_inodes+0x3cc/0xf10 fs/fs-writeback.c:1721
 wb_writeback+0x28e/0x700 fs/fs-writeback.c:1905
 wb_do_writeback+0x101/0x510 fs/fs-writeback.c:2050
 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2091
 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276
 worker_thread+0x636/0xae0 kernel/workqueue.c:2422
 kthread+0x1d0/0x1f0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff888106420258 of 8 bytes by task 1641 on cpu 1:
 inode_is_dirtytime_only include/linux/fs.h:2423 [inline]
 __ext4_update_other_inode_time+0x48/0x5c0 fs/ext4/inode.c:4963
 ext4_update_other_inodes_time fs/ext4/inode.c:5006 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5135 [inline]
 ext4_mark_iloc_dirty+0x12b6/0x1750 fs/ext4/inode.c:5724
 __ext4_mark_inode_dirty+0x4db/0x5b0 fs/ext4/inode.c:5918
 ext4_da_write_end+0x4c7/0x730 fs/ext4/inode.c:3100
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3671
 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000020107 -> 0x0000000000000100

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1641 Comm: rs:main Q:Reg Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================