================================================================== BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space write to 0xffff888087652cf8 of 4 bytes by task 2165 on cpu 1: ext4_da_reserve_space+0x12b/0x220 fs/ext4/inode.c:1476 ext4_insert_delayed_block fs/ext4/inode.c:1641 [inline] ext4_da_map_blocks fs/ext4/inode.c:1755 [inline] ext4_da_get_block_prep+0x4d5/0x990 fs/ext4/inode.c:1819 ext4_block_write_begin+0x433/0xb60 fs/ext4/inode.c:1061 ext4_da_write_begin+0x4e8/0xa30 fs/ext4/inode.c:2997 generic_perform_write+0x196/0x390 mm/filemap.c:3299 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:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff888087652cf8 of 4 bytes by task 2129 on cpu 0: ext4_alloc_da_blocks+0x1f/0x130 fs/ext4/inode.c:3112 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 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0x6da/0x16e0 kernel/exit.c:805 do_group_exit+0xcb/0x180 kernel/exit.c:903 get_signal+0x106d/0x1650 kernel/signal.c:2743 do_signal+0x25/0x270 arch/x86/kernel/signal.c:810 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline] __prepare_exit_to_usermode+0x127/0x230 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: 0 PID: 2129 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 ==================================================================