EXT4-fs error (device loop0): ext4_free_blocks:6223: comm syz.0.18: Freeing blocks not in datazone - block = 41, count = 1
EXT4-fs (loop0): Remounting filesystem read-only
==================================================================
BUG: KASAN: out-of-bounds in ext4_ext_rm_leaf fs/ext4/extents.c:2717 [inline]
BUG: KASAN: out-of-bounds in ext4_ext_remove_space+0x1eef/0x4180 fs/ext4/extents.c:2939
Read of size 18446744073709551604 at addr ffff88812a4ee018 by task syz.0.18/487

CPU: 0 PID: 487 Comm: syz.0.18 Not tainted 5.15.189-syzkaller-1081280-gf32b52534f1d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 ext4_ext_rm_leaf fs/ext4/extents.c:2717 [inline]
 ext4_ext_remove_space+0x1eef/0x4180 fs/ext4/extents.c:2939
 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4131
 ext4_fallocate+0x2b6/0x1de0 fs/ext4/extents.c:4765
 vfs_fallocate+0x4b4/0x590 fs/open.c:309
 ksys_fallocate fs/open.c:332 [inline]
 __do_sys_fallocate fs/open.c:340 [inline]
 __se_sys_fallocate fs/open.c:338 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:338
 x64_sys_call+0x7ec/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:286
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5477914ff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5477375038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f5477acd058 RCX: 00007f5477914ff9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007f5477987296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001a00 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f5477acd058 R15: 00007fff5d494798
 </TASK>

The buggy address belongs to the page:
page:ffffea0004a93b80 refcount:2 mapcount:0 mapping:ffff88810928f258 index:0x27 pfn:0x12a4ee
memcg:ffff88810a91e780
aops:def_blk_aops ino:700000
flags: 0x4000000000002036(referenced|uptodate|lru|active|private|zone=1)
raw: 4000000000002036 ffffea0004a9a948 ffff88810a909130 ffff88810928f258
raw: 0000000000000027 ffff8881118ee150 00000002ffffffff ffff88810a91e780
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 484, ts 53466539433, free_ts 53043568180
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485
 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5795
 __alloc_pages_node include/linux/gfp.h:595 [inline]
 alloc_pages_node include/linux/gfp.h:609 [inline]
 alloc_pages include/linux/gfp.h:622 [inline]
 __page_cache_alloc include/linux/pagemap.h:305 [inline]
 pagecache_get_page+0xa82/0xda0 mm/filemap.c:1954
 find_or_create_page include/linux/pagemap.h:418 [inline]
 grow_dev_page fs/buffer.c:949 [inline]
 grow_buffers fs/buffer.c:1014 [inline]
 __getblk_slow fs/buffer.c:1041 [inline]
 __getblk_gfp+0x238/0x7d0 fs/buffer.c:1336
 sb_getblk_gfp include/linux/buffer_head.h:368 [inline]
 ext4_ext_grow_indepth fs/ext4/extents.c:1330 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1431 [inline]
 ext4_ext_insert_extent+0x110f/0x47a0 fs/ext4/extents.c:2103
 ext4_split_extent_at+0x798/0xe90 fs/ext4/extents.c:3235
 ext4_split_extent+0x1d7/0x4e0 fs/ext4/extents.c:3354
 ext4_split_convert_extents fs/ext4/extents.c:3715 [inline]
 ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3876 [inline]
 ext4_ext_map_blocks+0x1b6f/0x6280 fs/ext4/extents.c:4231
 ext4_map_blocks+0x97b/0x1b20 fs/ext4/inode.c:674
 _ext4_get_block+0x1da/0x4e0 fs/ext4/inode.c:817
 ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:848
 ext4_block_write_begin+0x556/0x1150 fs/ext4/inode.c:1102
 ext4_write_begin+0x638/0x1220 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x2fa/0xb60 fs/ext4/inode.c:2988
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
 free_unref_page_list+0x134/0x9d0 mm/page_alloc.c:3671
 release_pages+0xfda/0x1030 mm/swap.c:1014
 __pagevec_release+0x71/0xe0 mm/swap.c:1034
 pagevec_release include/linux/pagevec.h:81 [inline]
 shmem_undo_range+0x53f/0x13d0 mm/shmem.c:969
 shmem_truncate_range mm/shmem.c:1068 [inline]
 shmem_evict_inode+0x1fd/0x9c0 mm/shmem.c:1150
 evict+0x485/0x870 fs/inode.c:650
 iput_final fs/inode.c:1779 [inline]
 iput+0x635/0x7c0 fs/inode.c:1805
 dentry_unlink_inode+0x32f/0x3e0 fs/dcache.c:380
 __dentry_kill+0x44f/0x650 fs/dcache.c:586
 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
 dput+0x47/0x90 fs/dcache.c:893
 __fput+0x580/0x8b0 fs/file_table.c:319
 ____fput+0x15/0x20 fs/file_table.c:339
 task_work_run+0x127/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xa7e/0x27a0 kernel/exit.c:889

Memory state around the buggy address:
 ffff88812a4edf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812a4edf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812a4ee000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                            ^
 ffff88812a4ee080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812a4ee100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop0): __ext4_get_inode_loc:4352: comm syz.0.18: Invalid inode table block 0 in block_group 0
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0) in ext4_reserve_inode_write:5867: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): __ext4_ext_dirty:183: inode #16: comm syz.0.18: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): __ext4_get_inode_loc:4352: comm syz.0.18: Invalid inode table block 0 in block_group 0
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0) in ext4_reserve_inode_write:5867: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_punch_hole:4144: inode #16: comm syz.0.18: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only