================================================================== BUG: KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty write to 0xffff88812023d65c of 2 bytes by task 21 on cpu 1: ext4_ext_mark_initialized fs/ext4/ext4_extents.h:218 [inline] ext4_convert_unwritten_extents_endio fs/ext4/extents.c:3721 [inline] ext4_ext_handle_unwritten_extents+0x609/0xaa0 fs/ext4/extents.c:3854 ext4_ext_map_blocks+0x758/0x20c0 fs/ext4/extents.c:4124 ext4_map_blocks+0x6d3/0xf60 fs/ext4/inode.c:626 ext4_convert_unwritten_extents+0x16a/0x2d0 fs/ext4/extents.c:4755 ext4_convert_unwritten_io_end_vec+0xa4/0x130 fs/ext4/extents.c:4794 ext4_end_io_end fs/ext4/page-io.c:187 [inline] ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline] ext4_end_io_rsv_work+0x198/0x360 fs/ext4/page-io.c:274 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415 kthread+0x20d/0x230 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 read to 0xffff88812023d65c of 4 bytes by task 8256 on cpu 0: ext4_do_update_inode fs/ext4/inode.c:5042 [inline] ext4_mark_iloc_dirty+0xd6c/0x1660 fs/ext4/inode.c:5624 __ext4_mark_inode_dirty+0x448/0x630 fs/ext4/inode.c:5818 ext4_da_write_end+0x4aa/0x760 fs/ext4/inode.c:3082 generic_perform_write+0x23b/0x390 mm/filemap.c:3310 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:270 ext4_file_write_iter+0x76f/0x1010 include/linux/fs.h:804 call_write_iter include/linux/fs.h:1907 [inline] new_sync_write fs/read_write.c:484 [inline] __vfs_write+0x2d8/0x340 fs/read_write.c:497 vfs_write+0x19b/0x350 fs/read_write.c:559 ksys_write+0xce/0x180 fs/read_write.c:612 __do_sys_write fs/read_write.c:624 [inline] __se_sys_write fs/read_write.c:621 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:621 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 8256 Comm: rs:main Q:Reg Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================