==================================================================
BUG: KASAN: out-of-bounds in ext4_ext_rm_leaf fs/ext4/extents.c:2715 [inline]
BUG: KASAN: out-of-bounds in ext4_ext_remove_space+0x1ee9/0x4180 fs/ext4/extents.c:2937
Read of size 18446744073709551604 at addr ffff8881255d9018 by task syz.0.15/444

CPU: 0 PID: 444 Comm: syz.0.15 Not tainted 5.15.184-syzkaller-1080569-g4b77ae0e7f58 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:2715 [inline]
 ext4_ext_remove_space+0x1ee9/0x4180 fs/ext4/extents.c:2937
 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4131
 ext4_fallocate+0x2b6/0x1de0 fs/ext4/extents.c:4763
 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: 0033:0x7f7b9290eff9
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:00007f7b9236f038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f7b92ac7058 RCX: 00007f7b9290eff9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007f7b92981296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001a00 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f7b92ac7058 R15: 00007ffd30eb9bf8
 </TASK>

The buggy address belongs to the page:
page:ffffea0004957640 refcount:2 mapcount:0 mapping:ffff888109315358 index:0x27 pfn:0x1255d9
memcg:ffff888121124000
aops:def_blk_aops ino:700000
flags: 0x4000000000002036(referenced|uptodate|lru|active|private|zone=1)
raw: 4000000000002036 ffffea00049575c8 ffffea0004b5c208 ffff888109315358
raw: 0000000000000027 ffff88812c83f690 00000002ffffffff ffff888121124000
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 440, ts 54642407506, free_ts 54572673376
 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:5781
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 __page_cache_alloc include/linux/pagemap.h:305 [inline]
 pagecache_get_page+0x8c7/0xc20 mm/filemap.c:1946
 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:2102
 ext4_split_extent_at+0x798/0xe90 fs/ext4/extents.c:3234
 ext4_split_extent+0x1d7/0x4e0 fs/ext4/extents.c:3353
 ext4_split_convert_extents fs/ext4/extents.c:3714 [inline]
 ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3875 [inline]
 ext4_ext_map_blocks+0x1b6c/0x6270 fs/ext4/extents.c:4230
 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+0x1076/0x10d0 mm/swap.c:1009
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x175/0x300 mm/mmu_gather.c:338
 unmap_region+0x315/0x360 mm/mmap.c:2680
 __do_munmap+0xa0e/0xfe0 mm/mmap.c:2913
 __vm_munmap+0x15b/0x2a0 mm/mmap.c:2966
 __do_sys_munmap mm/mmap.c:2992 [inline]
 __se_sys_munmap mm/mmap.c:2988 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:2988
 x64_sys_call+0xc9/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 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

Memory state around the buggy address:
 ffff8881255d8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881255d8f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881255d9000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                            ^
 ffff8881255d9080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881255d9100: 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.0.15: 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:5866: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): __ext4_ext_dirty:183: inode #16: comm syz.0.15: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): __ext4_get_inode_loc:4352: comm syz.0.15: 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:5866: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_punch_hole:4144: inode #16: comm syz.0.15: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only