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BUG: KASAN: use-after-free in ext4_inode_block_valid+0x33b/0x3b0 fs/ext4/block_validity.c:255
Read of size 8 at addr ffff8882351562b8 by task syz-executor.1/10386

CPU: 1 PID: 10386 Comm: syz-executor.1 Not tainted 4.14.297-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 ext4_inode_block_valid+0x33b/0x3b0 fs/ext4/block_validity.c:255
 __check_block_validity.constprop.0+0x17a/0x2c0 fs/ext4/inode.c:423
 ext4_map_blocks+0x8dc/0x1730 fs/ext4/inode.c:738
 ext4_alloc_file_blocks.isra.0+0x24e/0x840 fs/ext4/extents.c:4732
 ext4_fallocate+0x713/0x1d80 fs/ext4/extents.c:5014
 vfs_fallocate+0x346/0x790 fs/open.c:319
 ioctl_preallocate+0x132/0x1a0 fs/ioctl.c:481
 file_ioctl fs/ioctl.c:497 [inline]
 do_vfs_ioctl+0xd94/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3

Allocated by task 1:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc+0x124/0x3c0 mm/slab.c:3552
 add_system_zone+0x108/0x650 fs/ext4/block_validity.c:78
 ext4_setup_system_zone+0x325/0x8c0 fs/ext4/block_validity.c:197
 ext4_fill_super+0x63a9/0xb3c0 fs/ext4/super.c:4407
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2572 [inline]
 do_mount+0xe65/0x2a30 fs/namespace.c:2905
 SYSC_mount fs/namespace.c:3121 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3098
 do_mount_root+0x30/0x1b0 init/do_mounts.c:366
 mount_block_root+0x2bc/0x5a3 init/do_mounts.c:395
 mount_root+0x1c4/0x1f3 init/do_mounts.c:540
 prepare_namespace+0x1d6/0x212 init/do_mounts.c:599
 kernel_init_freeable+0x609/0x626 init/main.c:1099
 kernel_init+0xd/0x15b init/main.c:1006
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406

Freed by task 10384:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758
 ext4_release_system_zone+0x79/0x110 fs/ext4/block_validity.c:230
 ext4_setup_system_zone+0x3a9/0x8c0 fs/ext4/block_validity.c:188
 ext4_remount+0xfa2/0x1df0 fs/ext4/super.c:5387
 do_remount_sb+0x150/0x530 fs/super.c:868
 do_remount fs/namespace.c:2393 [inline]
 do_mount+0x15f3/0x2a30 fs/namespace.c:2896
 SYSC_mount fs/namespace.c:3121 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3098
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3

The buggy address belongs to the object at ffff8882351562a0
 which belongs to the cache ext4_system_zone of size 40
The buggy address is located 24 bytes inside of
 40-byte region [ffff8882351562a0, ffff8882351562c8)
The buggy address belongs to the page:
page:ffffea0008d45580 count:1 mapcount:0 mapping:ffff888235156000 index:0xffff888235156fb9
flags: 0x57ff00000000100(slab)
raw: 057ff00000000100 ffff888235156000 ffff888235156fb9 000000010000001b
raw: ffff8882392dad38 ffff8882392dad38 ffff8880b1234d80 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888235156180: fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb
 ffff888235156200: fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb
>ffff888235156280: fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb
                                        ^
 ffff888235156300: fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc
 ffff888235156380: fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb
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