================================================================== BUG: KCSAN: data-race in ext4_write_end / mpage_process_page_bufs write to 0xffff8881373a3c08 of 8 bytes by task 8604 on cpu 1: i_size_write include/linux/fs.h:916 [inline] ext4_update_inode_size fs/ext4/ext4.h:3421 [inline] ext4_write_end+0x1c9/0x7f0 fs/ext4/inode.c:1311 ext4_da_write_end+0x93/0x730 fs/ext4/inode.c:3085 generic_perform_write+0x23a/0x3d0 mm/filemap.c:3784 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269 ext4_file_write_iter+0x2e7/0x11a0 fs/ext4/file.c:519 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x77d/0x8c0 fs/read_write.c:594 ksys_write+0xce/0x180 fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:656 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 0xffff8881373a3c08 of 8 bytes by task 563 on cpu 0: i_size_read include/linux/fs.h:894 [inline] mpage_process_page_bufs+0x34/0x560 fs/ext4/inode.c:2198 mpage_prepare_extent_to_map+0x4e6/0x640 fs/ext4/inode.c:2632 ext4_writepages+0x9e8/0x1d30 fs/ext4/inode.c:2804 do_writepages+0x8b/0x160 mm/page-writeback.c:2353 __writeback_single_inode+0x80/0x440 fs/fs-writeback.c:1613 writeback_sb_inodes+0x563/0xd30 fs/fs-writeback.c:1878 wb_writeback+0x28e/0x700 fs/fs-writeback.c:2051 wb_do_writeback+0x101/0x510 fs/fs-writeback.c:2196 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2237 process_one_work+0x402/0x910 kernel/workqueue.c:2297 worker_thread+0x636/0xae0 kernel/workqueue.c:2444 kthread+0x262/0x280 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 value changed: 0x0000000000175000 -> 0x0000000000176000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 563 Comm: kworker/u4:11 Tainted: G W 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ================================================================== EXT4-fs: 70 callbacks suppressed EXT4-fs (sda1): Delayed block allocation failed for inode 16383 at logical offset 683 with max blocks 45 with error 28 EXT4-fs (sda1): This should not happen!! Data will be lost EXT4-fs (sda1): Total free blocks count 0 EXT4-fs (sda1): Free/Dirty block details EXT4-fs (sda1): free_blocks=15463 EXT4-fs (sda1): dirty_blocks=3842 EXT4-fs (sda1): Block reservation details EXT4-fs (sda1): i_reserved_data_blocks=333 EXT4-fs: 78 callbacks suppressed EXT4-fs (sda1): Delayed block allocation failed for inode 14672 at logical offset 2071 with max blocks 56 with error 28 EXT4-fs (sda1): This should not happen!! Data will be lost EXT4-fs (sda1): Total free blocks count 0 EXT4-fs (sda1): Free/Dirty block details EXT4-fs (sda1): free_blocks=15463 EXT4-fs (sda1): dirty_blocks=4418 EXT4-fs (sda1): Block reservation details EXT4-fs (sda1): i_reserved_data_blocks=326