================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x2d5/0x330 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff8801c9f63750 by task syz-executor3/23189 CPU: 1 PID: 23189 Comm: syz-executor3 Not tainted 4.19.0-rc8-next-20181018+ #97 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+0x95/0x2b0 fs/ext4/inode.c:1016 __ext4_read_dirblock+0x37/0x940 fs/ext4/namei.c:101 ext4_add_entry+0x535/0xc10 fs/ext4/namei.c:2077 ext4_add_nondir+0x27/0x90 fs/ext4/namei.c:2412 ext4_symlink+0x752/0x1130 fs/ext4/namei.c:3162 vfs_symlink+0x37a/0x5d0 fs/namei.c:4127 do_symlinkat+0x242/0x2d0 fs/namei.c:4154 __do_sys_symlink fs/namei.c:4173 [inline] __se_sys_symlink fs/namei.c:4171 [inline] __x64_sys_symlink+0x59/0x80 fs/namei.c:4171 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457297 Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 9d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffcc2b7ddc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457297 RDX: 00007ffcc2b7de43 RSI: 00000000004bcfa7 RDI: 00007ffcc2b7de30 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013 R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000001 R14: 00000000000001dd R15: 0000000000000003 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 23161: 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 ffff8801c9f63738 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff8801c9f63738, ffff8801c9f63760) The buggy address belongs to the page: page:ffffea000727d8c0 count:1 mapcount:0 mapping:ffff8801d4bb8180 index:0xffff8801c9f63fb9 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffff8801d4bb9538 ffff8801d4bb9538 ffff8801d4bb8180 raw: ffff8801c9f63fb9 ffff8801c9f63000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c9f63600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c9f63680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801c9f63700: fc fc fc fc fc fc fc fb fb fb fb fb fc fc fb fb ^ ffff8801c9f63780: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb ffff8801c9f63800: 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