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EXT4-fs (sda1): re-mounted. Opts: noblock_validity,
BUG: KASAN: use-after-free in ext4_data_block_valid+0x279/0x2d0 fs/ext4/block_validity.c:211
Read of size 8 at addr ffff8881d5c24bb0 by task syz-executor.4/7520

CPU: 1 PID: 7520 Comm: syz-executor.4 Not tainted 4.14.154+ #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+0x7c/0x1d0 fs/ext4/inode.c:1022
 __ext4_read_dirblock+0x33/0x800 fs/ext4/namei.c:111
 htree_dirblock_to_tree+0xa6/0x560 fs/ext4/namei.c:995
 ext4_htree_fill_tree+0x1fb/0x8a0 fs/ext4/namei.c:1114
 ext4_dx_readdir fs/ext4/dir.c:571 [inline]
 ext4_readdir+0x1197/0x23e0 fs/ext4/dir.c:120
 iterate_dir+0x1a5/0x5f0 fs/readdir.c:52
 SYSC_getdents fs/readdir.c:232 [inline]
 SyS_getdents+0x145/0x290 fs/readdir.c:213
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45898b
RSP: 002b:00007ffcfd2d4280 EFLAGS: 00000202 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 0000000000e20970 RCX: 000000000045898b
RDX: 0000000000008000 RSI: 0000000000e20970 RDI: 0000000000000003
RBP: 0000000000e20970 R08: 0000000000000001 R09: 0000000000e1f940
R10: 0000000000000000 R11: 0000000000000202 R12: ffffffffffffffd4
R13: 0000000000000016 R14: 0000000000000000 R15: 00007ffcfd2d5420

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+0x2e2/0x470 fs/ext4/block_validity.c:169
 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 7902:
 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 ffff8881d5c24b98
 which belongs to the cache ext4_system_zone of size 40
The buggy address is located 24 bytes inside of
 40-byte region [ffff8881d5c24b98, ffff8881d5c24bc0)
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
The buggy address belongs to the page:
page:ffffea0007570900 count:1 mapcount:0 mapping:          (null) index:0xffff8881d5c24c40
flags: 0x4000000000000200(slab)
raw: 4000000000000200 0000000000000000 ffff8881d5c24c40 0000000180490017
raw: dead000000000100 dead000000000200 ffff8881d90b0400 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d5c24a80: fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb
 ffff8881d5c24b00: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb
>ffff8881d5c24b80: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc
                                     ^
 ffff8881d5c24c00: fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc fc
 ffff8881d5c24c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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