================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x279/0x2d0 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff8881d591a0f8 by task blkid/13826 CPU: 0 PID: 13826 Comm: blkid Not tainted 4.14.155-syzkaller #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xe5/0x154 lib/dump_stack.c:58 print_address_description+0x60/0x226 mm/kasan/report.c:187 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316 ext4_data_block_valid+0x279/0x2d0 fs/ext4/block_validity.c:211 __check_block_validity.constprop.0+0xba/0x200 fs/ext4/inode.c:402 ext4_map_blocks+0xdc9/0x1600 fs/ext4/inode.c:592 ext4_getblk+0x344/0x420 fs/ext4/inode.c:972 ext4_bread_batch+0x78/0x340 fs/ext4/inode.c:1042 __ext4_find_entry+0x447/0xcd0 fs/ext4/namei.c:1516 ext4_lookup_entry fs/ext4/namei.c:1615 [inline] ext4_lookup+0x15e/0x5b0 fs/ext4/namei.c:1683 lookup_slow+0x226/0x440 fs/namei.c:1794 walk_component+0x6d0/0xbf0 fs/namei.c:1923 lookup_last fs/namei.c:2391 [inline] path_lookupat.isra.0+0x1ce/0x7e0 fs/namei.c:2441 filename_lookup+0x335/0x3b0 fs/namei.c:2477 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:413 [inline] SyS_faccessat+0x23a/0x6b0 fs/open.c:362 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f85ba1a5267 RSP: 002b:00007ffdfba622a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 0000000000400f31 RCX: 00007f85ba1a5267 RDX: 00000000000033ef RSI: 0000000000000000 RDI: 00007f85ba1a92e6 RBP: 00007f85ba3a8000 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 00007f85ba3b01c8 R13: 00007f85ba3a8718 R14: 00000000000033ef R15: 00007f85ba3b0570 Allocated by task 1: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc.part.0+0x53/0xc0 mm/kasan/common.c:501 slab_post_alloc_hook mm/slab.h:439 [inline] slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2800 [inline] kmem_cache_alloc+0xee/0x360 mm/slub.c:2805 add_system_zone+0x29b/0x530 fs/ext4/block_validity.c:85 ext4_setup_system_zone+0x253/0x470 fs/ext4/block_validity.c:160 ext4_fill_super+0x65f2/0xb290 fs/ext4/super.c:4452 mount_bdev+0x2b6/0x360 fs/super.c:1151 mount_fs+0x277/0x312 fs/super.c:1257 vfs_kern_mount.part.0+0xc7/0x4a0 fs/namespace.c:1056 vfs_kern_mount fs/namespace.c:1038 [inline] do_new_mount fs/namespace.c:2573 [inline] do_mount+0x3f6/0x26a0 fs/namespace.c:2903 SYSC_mount fs/namespace.c:3119 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3096 do_mount_root init/do_mounts.c:366 [inline] mount_block_root+0x345/0x70a init/do_mounts.c:395 prepare_namespace+0x1d1/0x20d init/do_mounts.c:599 kernel_init_freeable+0x393/0x3b0 init/main.c:1116 kernel_init+0xd/0x164 init/main.c:1023 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404 0xffffffffffffffff Freed by task 13834: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x164/0x210 mm/kasan/common.c:463 slab_free_hook mm/slub.c:1407 [inline] slab_free_freelist_hook mm/slub.c:1458 [inline] slab_free mm/slub.c:3039 [inline] kmem_cache_free+0xd7/0x3b0 mm/slub.c:3055 ext4_release_system_zone+0x68/0xe0 fs/ext4/block_validity.c:187 ext4_setup_system_zone+0x3a3/0x470 fs/ext4/block_validity.c:151 ext4_remount+0xdfb/0x1d10 fs/ext4/super.c:5408 do_remount_sb2+0x35a/0x5e0 fs/super.c:880 do_remount fs/namespace.c:2388 [inline] do_mount+0x1305/0x26a0 fs/namespace.c:2894 SYSC_mount fs/namespace.c:3119 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 0xffffffffffffffff The buggy address belongs to the object at ffff8881d591a0e0 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff8881d591a0e0, ffff8881d591a108) The buggy address belongs to the page: page:ffffea0007564680 count:1 mapcount:0 mapping: (null) index:0xffff8881d591adc8 flags: 0x4000000000000200(slab) raw: 4000000000000200 0000000000000000 ffff8881d591adc8 000000018049000d raw: dead000000000100 dead000000000200 ffff8881d912d200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d5919f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881d591a000: fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb >ffff8881d591a080: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb ^ ffff8881d591a100: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc ffff8881d591a180: fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb ================================================================== EXT4-fs (sda1): re-mounted. Opts: noblock_validity,data_err=ignore,sb=0x000000000000c0d5,lazytime,jqfmt=vfsold,