EXT4-fs error (device loop2): ext4_validate_block_bitmap:420: comm syz.2.207: bg 0: bad block bitmap checksum
==================================================================
BUG: KASAN: out-of-bounds in ext4_xattr_set_entry+0x13ba/0x3940 fs/ext4/xattr.c:1736
Read of size 18446744073709551600 at addr ffff88812b80bed8 by task syz.2.207/1079

CPU: 1 PID: 1079 Comm: syz.2.207 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 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+0x249/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 ext4_xattr_set_entry+0x13ba/0x3940 fs/ext4/xattr.c:1736
 ext4_xattr_ibody_set+0x122/0x360 fs/ext4/xattr.c:2238
 ext4_destroy_inline_data_nolock+0x234/0x5d0 fs/ext4/inline.c:468
 ext4_convert_inline_data_to_extent fs/ext4/inline.c:633 [inline]
 ext4_try_to_write_inline_data+0x6ef/0x1190 fs/ext4/inline.c:774
 ext4_write_begin+0x243/0x12e0 fs/ext4/inode.c:1192
 generic_perform_write+0x2b7/0x690 mm/filemap.c:3870
 ext4_buffered_write_iter+0x4ed/0x670 fs/ext4/file.c:270
 ext4_file_write_iter+0x440/0x1540 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2212 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x835/0xfd0 fs/read_write.c:594
 ksys_write+0x149/0x250 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
 x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0033:0x7f8e3b93a819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8e3b79d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8e3bbb3fa0 RCX: 00007f8e3b93a819
RDX: 0000000000000050 RSI: 0000200000000440 RDI: 0000000000000004
RBP: 00007f8e3b9d0c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e3bbb4038 R14: 00007f8e3bbb3fa0 R15: 00007ffeaa1278a8
 </TASK>

The buggy address belongs to the page:
page:ffffea0004ae02c0 refcount:3 mapcount:1 mapping:ffff8881092885d8 index:0x1 pfn:0x12b80b
memcg:ffff8881002533c0
aops:def_blk_aops ino:700002
flags: 0x400000000002203e(referenced|uptodate|dirty|lru|active|private|mappedtodisk|zone=1)
raw: 400000000002203e ffffea0004741308 ffffea0004b8a088 ffff8881092885d8
raw: 0000000000000001 ffff888120ea1c78 0000000300000000 ffff8881002533c0
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 399, ts 60171620871, free_ts 60028916893
 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+0x2d3a/0x2dc0 mm/page_alloc.c:4485
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5822
 __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]
 page_cache_ra_unbounded+0x2d5/0x9a0 mm/readahead.c:227
 do_page_cache_ra mm/readahead.c:280 [inline]
 force_page_cache_ra+0x3fd/0x460 mm/readahead.c:312
 page_cache_sync_ra+0x2b4/0x430 mm/readahead.c:590
 page_cache_sync_readahead include/linux/pagemap.h:831 [inline]
 filemap_get_pages mm/filemap.c:2569 [inline]
 filemap_read+0x694/0x2040 mm/filemap.c:2654
 generic_file_read_iter+0xac/0x400 mm/filemap.c:2814
 blkdev_read_iter+0x12f/0x160 block/fops.c:563
 call_read_iter include/linux/fs.h:2206 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x6c9/0xc40 fs/read_write.c:485
 ksys_read+0x149/0x250 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:631
 x64_sys_call+0x96d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 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
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+0x13a/0x9d0 mm/page_alloc.c:3671
 release_pages+0x1006/0x1060 mm/swap.c:1015
 __pagevec_release+0x71/0xe0 mm/swap.c:1035
 pagevec_release include/linux/pagevec.h:81 [inline]
 __invalidate_mapping_pages+0x4fe/0x700 mm/truncate.c:517
 invalidate_mapping_pages+0x27/0x30 mm/truncate.c:541
 invalidate_bdev+0xa6/0x150 block/bdev.c:88
 ext4_put_super+0x6cb/0xa70 fs/ext4/super.c:1247
 generic_shutdown_super+0x151/0x330 fs/super.c:475
 kill_block_super+0x7f/0xf0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x100 fs/super.c:335
 deactivate_super+0xaf/0xe0 fs/super.c:366
 cleanup_mnt+0x45b/0x510 fs/namespace.c:1148
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1155
 task_work_run+0x127/0x190 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181

Memory state around the buggy address:
 ffff88812b80bd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812b80be00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812b80be80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                    ^
 ffff88812b80bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812b80bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop2): ext4_ind_map_blocks:604: inode #15: comm syz.2.207: Can't allocate blocks for non-extent mapped inodes with bigalloc