================================================================== BUG: KCSAN: data-race in ext4_writepages / generic_write_end write to 0xffff88811f1913b8 of 8 bytes by task 12109 on cpu 0: i_size_write include/linux/fs.h:897 [inline] generic_write_end+0x99/0x220 fs/buffer.c:2187 ext4_da_write_end+0x57e/0x760 fs/ext4/inode.c:3092 generic_perform_write+0x23b/0x390 mm/filemap.c:3329 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:270 ext4_file_write_iter+0x76f/0x1010 include/linux/fs.h:805 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 0xffff88811f1913b8 of 8 bytes by task 21 on cpu 1: i_size_read include/linux/fs.h:875 [inline] mpage_submit_page fs/ext4/inode.c:2076 [inline] mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2469 [inline] ext4_writepages+0xe0e/0x1ef0 fs/ext4/inode.c:2782 do_writepages+0x7b/0x150 mm/page-writeback.c:2354 __writeback_single_inode+0x81/0x610 fs/fs-writeback.c:1452 writeback_sb_inodes+0x5ac/0xe40 fs/fs-writeback.c:1716 wb_writeback+0x2b8/0x730 fs/fs-writeback.c:1892 wb_do_writeback+0x108/0x610 fs/fs-writeback.c:2037 wb_workfn+0xc8/0x460 fs/fs-writeback.c:2078 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 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ==================================================================