==================================================================
BUG: KCSAN: data-race in ext4_set_iomap / writeback_single_inode

write to 0xffff888122476300 of 8 bytes by task 10601 on cpu 1:
 inode_sync_complete fs/fs-writeback.c:1197 [inline]
 writeback_single_inode+0x4a4/0x530 fs/fs-writeback.c:1578
 sync_inode fs/fs-writeback.c:2602 [inline]
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2622
 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
 ext4_sync_file+0x335/0x6e0 fs/ext4/fsync.c:170
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2882 [inline]
 iomap_dio_complete+0x2de/0x380 fs/iomap/direct-io.c:125
 iomap_dio_rw+0x874/0x8c0 fs/iomap/direct-io.c:572
 ext4_dio_write_iter fs/ext4/file.c:545 [inline]
 ext4_file_write_iter+0xda4/0x1010 fs/ext4/file.c:653
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x607/0x690 fs/read_write.c:578
 ksys_write+0xce/0x180 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888122476300 of 8 bytes by task 10617 on cpu 0:
 ext4_inode_datasync_dirty fs/ext4/inode.c:3306 [inline]
 ext4_set_iomap+0x138/0x3e0 fs/ext4/inode.c:3321
 ext4_iomap_begin_report+0x2f9/0x390 fs/ext4/inode.c:3568
 iomap_apply+0x8a/0x520 fs/iomap/apply.c:46
 iomap_fiemap+0x100/0x270 fs/iomap/fiemap.c:83
 ext4_fiemap+0x1ee/0x210 fs/ext4/extents.c:4910
 ioctl_fiemap fs/ioctl.c:216 [inline]
 do_vfs_ioctl+0x8e8/0xec0 fs/ioctl.c:705
 ksys_ioctl fs/ioctl.c:751 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0x81/0x130 fs/ioctl.c:760
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:760
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10617 Comm: syz-executor.0 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================