================================================================== BUG: KCSAN: data-race in ext4_write_end / mpage_process_page_bufs write to 0xffff888106b0f350 of 8 bytes by task 28747 on cpu 0: i_size_write include/linux/fs.h:871 [inline] ext4_update_inode_size fs/ext4/ext4.h:3359 [inline] ext4_write_end+0x1d7/0x820 fs/ext4/inode.c:1309 ext4_da_write_end+0x93/0x730 fs/ext4/inode.c:3079 generic_perform_write+0x22a/0x3c0 mm/filemap.c:3667 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_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888106b0f350 of 8 bytes by task 1201 on cpu 1: i_size_read include/linux/fs.h:849 [inline] mpage_process_page_bufs+0x34/0x560 fs/ext4/inode.c:2192 mpage_prepare_extent_to_map+0x4e6/0x640 fs/ext4/inode.c:2626 ext4_writepages+0x9d8/0x1d10 fs/ext4/inode.c:2798 do_writepages+0x7b/0x150 mm/page-writeback.c:2355 __writeback_single_inode+0x80/0x440 fs/fs-writeback.c:1610 writeback_sb_inodes+0x563/0xd10 fs/fs-writeback.c:1875 wb_writeback+0x28e/0x700 fs/fs-writeback.c:2048 wb_do_writeback+0x101/0x510 fs/fs-writeback.c:2193 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2234 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276 process_scheduled_works kernel/workqueue.c:2338 [inline] worker_thread+0x7ff/0xae0 kernel/workqueue.c:2424 kthread+0x262/0x280 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 value changed: 0x000000000038f000 -> 0x0000000000390000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 1201 Comm: kworker/u4:3 Tainted: G W 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ==================================================================