================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x2d5/0x330 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff8801d1ef9750 by task udevd/7917 CPU: 0 PID: 7917 Comm: udevd Not tainted 4.20.0-rc1-next-20181109+ #110 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 ext4_data_block_valid+0x2d5/0x330 fs/ext4/block_validity.c:211 __check_block_validity.constprop.80+0xc1/0x210 fs/ext4/inode.c:402 ext4_map_blocks+0x1021/0x1b50 fs/ext4/inode.c:592 ext4_getblk+0x4f2/0x630 fs/ext4/inode.c:966 ext4_bread_batch+0x7f/0x440 fs/ext4/inode.c:1036 ext4_find_entry+0xd49/0x1b70 fs/ext4/namei.c:1425 ext4_lookup+0x15b/0x700 fs/ext4/namei.c:1557 __lookup_slow+0x2b5/0x540 fs/namei.c:1671 lookup_slow+0x57/0x80 fs/namei.c:1688 walk_component+0x92b/0x2590 fs/namei.c:1810 link_path_walk.part.40+0xa61/0x1530 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_openat+0x270/0x5150 fs/namei.c:3533 do_filp_open+0x255/0x380 fs/namei.c:3564 do_open_execat+0x221/0x8e0 fs/exec.c:853 open_exec+0x53/0x70 fs/exec.c:885 load_elf_binary+0x96e/0x5620 fs/binfmt_elf.c:780 search_binary_handler+0x17d/0x570 fs/exec.c:1653 exec_binprm fs/exec.c:1695 [inline] __do_execve_file.isra.33+0x1661/0x25d0 fs/exec.c:1819 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1959 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f731c9db207 Code: 77 19 f4 48 89 d7 44 89 c0 0f 05 48 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 f7 d8 64 41 89 01 eb df b8 3b 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 02 f3 c3 48 8b 15 00 8c 2d 00 f7 d8 64 89 02 RSP: 002b:00007ffdfeb5cc88 EFLAGS: 00000206 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f731c9db207 RDX: 000000000181bb10 RSI: 00007ffdfeb5cd80 RDI: 00007ffdfeb5dd90 RBP: 0000000000625500 R08: 000000000000177e R09: 000000000000177e R10: 0000000000000000 R11: 0000000000000206 R12: 000000000181bb10 R13: 0000000000000007 R14: 000000000181b250 R15: 0000000000000005 Allocated by task 1: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 add_system_zone+0x2e5/0x5f0 fs/ext4/block_validity.c:85 ext4_setup_system_zone+0x208/0x520 fs/ext4/block_validity.c:169 ext4_fill_super+0x89eb/0xdba0 fs/ext4/super.c:4386 mount_bdev+0x314/0x3e0 fs/super.c:1356 ext4_mount+0x3c/0x50 fs/ext4/super.c:5896 legacy_get_tree+0x12f/0x260 fs/fs_context.c:714 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1795 do_new_mount fs/namespace.c:2716 [inline] do_mount+0x82a/0x1ff0 fs/namespace.c:3042 ksys_mount+0x12d/0x140 fs/namespace.c:3258 do_mount_root+0x35/0x1d3 init/do_mounts.c:388 mount_block_root+0x39c/0x6ed init/do_mounts.c:417 mount_root+0x358/0x39f init/do_mounts.c:562 prepare_namespace+0x26c/0x2ab init/do_mounts.c:621 kernel_init_freeable+0x69b/0x6b4 init/main.c:1159 kernel_init+0x11/0x1ae init/main.c:1060 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Freed by task 7909: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3760 ext4_release_system_zone+0x7c/0x110 fs/ext4/block_validity.c:187 ext4_setup_system_zone+0x3ef/0x520 fs/ext4/block_validity.c:151 ext4_remount+0x16fc/0x2980 fs/ext4/super.c:5341 legacy_reconfigure+0x14c/0x1c0 fs/fs_context.c:738 reconfigure_super+0x4c0/0xbb0 fs/super.c:982 do_remount fs/namespace.c:2434 [inline] do_mount+0x1ab4/0x1ff0 fs/namespace.c:3033 ksys_mount+0x12d/0x140 fs/namespace.c:3258 __do_sys_mount fs/namespace.c:3272 [inline] __se_sys_mount fs/namespace.c:3269 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3269 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d1ef9738 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff8801d1ef9738, ffff8801d1ef9760) The buggy address belongs to the page: page:ffffea000747be40 count:1 mapcount:0 mapping:ffff8801d45d4240 index:0xffff8801d1ef9fb9 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffff8801d45d5238 ffff8801d45d5238 ffff8801d45d4240 raw: ffff8801d1ef9fb9 ffff8801d1ef9000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d1ef9600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d1ef9680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801d1ef9700: fc fc fc fc fc fc fc fb fb fb fb fb fc fc fb fb ^ ffff8801d1ef9780: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb ffff8801d1ef9800: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc ================================================================== EXT4-fs (sda1): re-mounted. Opts: noblock_validity,,errors=continue netlink: 2 bytes leftover after parsing attributes in process `syz-executor0'. FAT-fs (loop3): error, fat_get_cluster: invalid cluster chain (i_pos 0) FAT-fs (loop3): Filesystem has been set read-only