================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x2d5/0x330 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff8801c9dc0750 by task udevd/5517 CPU: 0 PID: 5517 Comm: udevd Not tainted 4.19.0-rc8-next-20181019+ #98 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.78+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:2269 [inline] path_lookupat.isra.43+0xf7/0xc00 fs/namei.c:2317 filename_lookup+0x26a/0x520 fs/namei.c:2348 user_path_at_empty+0x40/0x50 fs/namei.c:2608 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0x129/0x210 fs/stat.c:185 vfs_stat include/linux/fs.h:3157 [inline] __do_sys_newstat+0x8f/0x110 fs/stat.c:339 __se_sys_newstat fs/stat.c:335 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:335 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f87dc7f6c65 Code: 00 00 00 e8 5d 01 00 00 48 83 c4 18 c3 90 90 90 90 90 90 90 90 83 ff 01 48 89 f0 77 18 48 89 c7 48 89 d6 b8 04 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 17 f3 c3 90 48 8b 05 a1 51 2b 00 64 c7 00 16 RSP: 002b:00007ffd789c46f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 00000000017e38dc RCX: 00007f87dc7f6c65 RDX: 00007ffd789c4770 RSI: 00007ffd789c4770 RDI: 00007ffd789c4c00 RBP: 00000000017cee90 R08: 0000000000000000 R09: 00007ffd789c4c10 R10: fffffffffffff657 R11: 0000000000000246 R12: 00000000017cf600 R13: 0000000000625500 R14: 00000000017ce250 R15: 00000000017d3e10 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+0x8180/0xdbb0 fs/ext4/super.c:4386 mount_bdev+0x314/0x3e0 fs/super.c:1356 ext4_mount+0x3c/0x50 fs/ext4/super.c:5895 legacy_get_tree+0x131/0x460 fs/fs_context.c:718 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1795 do_new_mount fs/namespace.c:2648 [inline] do_mount+0x70c/0x1d90 fs/namespace.c:2974 ksys_mount+0x12d/0x140 fs/namespace.c:3190 do_mount_root+0x35/0x1d3 init/do_mounts.c:388 mount_block_root+0x39c/0x6ed init/do_mounts.c:417 mount_root+0x2d3/0x31a init/do_mounts.c:562 prepare_namespace+0x26c/0x2ab init/do_mounts.c:621 kernel_init_freeable+0x69b/0x6b9 init/main.c:1170 kernel_init+0x11/0x1ae init/main.c:1071 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Freed by task 10388: 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:5340 legacy_reconfigure+0x14c/0x1c0 fs/fs_context.c:754 reconfigure_super+0x4c0/0xbb0 fs/super.c:982 do_remount fs/namespace.c:2419 [inline] do_mount+0x18b9/0x1d90 fs/namespace.c:2965 ksys_mount+0x12d/0x140 fs/namespace.c:3190 __do_sys_mount fs/namespace.c:3204 [inline] __se_sys_mount fs/namespace.c:3201 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3201 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 ffff8801c9dc0738 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff8801c9dc0738, ffff8801c9dc0760) The buggy address belongs to the page: page:ffffea0007277000 count:1 mapcount:0 mapping:ffff8801d4ad5600 index:0xffff8801c9dc0fb9 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffff8801d4adcd38 ffff8801d4adcd38 ffff8801d4ad5600 raw: ffff8801c9dc0fb9 ffff8801c9dc0000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c9dc0600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c9dc0680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801c9dc0700: fc fc fc fc fc fc fc fb fb fb fb fb fc fc fb fb ^ ffff8801c9dc0780: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb ffff8801c9dc0800: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc ================================================================== EXT4-fs (sda1): re-mounted. Opts: noblock_validity,grpid,usrquota,errors=continue,dioread_nolock,sb=0x0000000000000006,,errors=continue