================================================================== BUG: KCSAN: data-race in ext4_writepages / generic_write_end write to 0xffff8880bb4ab778 of 8 bytes by task 19816 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] do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:713 do_iter_write+0x10e/0x470 fs/read_write.c:1018 vfs_iter_write+0x4c/0x70 fs/read_write.c:1059 iter_file_splice_write+0x41a/0x770 fs/splice.c:750 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x95/0x160 fs/splice.c:1016 splice_direct_to_actor+0x365/0x660 fs/splice.c:971 do_splice_direct+0xf2/0x170 fs/splice.c:1059 do_sendfile+0x562/0xb10 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880bb4ab778 of 8 bytes by task 19813 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 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:421 __filemap_fdatawrite mm/filemap.c:429 [inline] filemap_flush+0x1f/0x30 mm/filemap.c:456 ext4_alloc_da_blocks+0x4c/0x130 fs/ext4/inode.c:3146 ext4_release_file+0x5b/0x1c0 fs/ext4/file.c:142 __fput+0x1df/0x460 fs/file_table.c:281 ____fput+0x11/0x20 fs/file_table.c:314 task_work_run+0x8e/0x110 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:239 [inline] __prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:269 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:352 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:393 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 19813 Comm: syz-executor.0 Not tainted 5.8.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================