================================================================== BUG: KCSAN: data-race in copy_page_to_iter / ext4_setup_super write to 0xffff8881455ea43a of 2 bytes by task 21639 on cpu 0: ext4_setup_super+0x23f/0x4d0 fs/ext4/super.c:2696 ext4_fill_super+0x57b0/0x8010 fs/ext4/super.c:4974 mount_bdev+0x1e8/0x290 fs/super.c:1368 ext4_mount+0x2d/0x40 fs/ext4/super.c:6632 legacy_get_tree+0x70/0xc0 fs/fs_context.c:592 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x11d4/0x1ce0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3433 __x64_sys_mount+0x63/0x70 fs/namespace.c:3433 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881455ea000 of 1377 bytes by task 21597 on cpu 1: instrument_copy_to_user include/linux/instrumented.h:119 [inline] copyout lib/iov_iter.c:188 [inline] copy_page_to_iter_iovec lib/iov_iter.c:260 [inline] copy_page_to_iter+0x320/0x860 lib/iov_iter.c:979 filemap_read+0xf06/0x1230 mm/filemap.c:2621 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2717 blkdev_read_iter+0xb3/0xc0 fs/block_dev.c:1720 call_read_iter include/linux/fs.h:2110 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x565/0x5d0 fs/read_write.c:496 ksys_read+0xce/0x180 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:642 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 21597 Comm: systemd-udevd Not tainted 5.12.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================