EXT4-fs error (device loop4): ext4_validate_block_bitmap:420: comm syz.4.1400: bg 0: bad block bitmap checksum
==================================================================
BUG: KASAN: out-of-bounds in ext4_xattr_set_entry+0x1339/0x36c0 fs/ext4/xattr.c:1741
Read of size 18446744073709551600 at addr ffff88810d79fed8 by task syz.4.1400/6428

CPU: 0 PID: 6428 Comm: syz.4.1400 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 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_xattr_set_entry+0x1339/0x36c0 fs/ext4/xattr.c:1741
 ext4_xattr_ibody_set+0x122/0x360 fs/ext4/xattr.c:2244
 ext4_destroy_inline_data_nolock+0x1da/0x590 fs/ext4/inline.c:455
 ext4_convert_inline_data_to_extent fs/ext4/inline.c:619 [inline]
 ext4_try_to_write_inline_data+0x621/0x1140 fs/ext4/inline.c:759
 ext4_write_begin+0x219/0x15a0 fs/ext4/inode.c:1192
 generic_perform_write+0x2be/0x510 mm/filemap.c:3509
 ext4_buffered_write_iter+0x4b8/0x640 fs/ext4/file.c:271
 ext4_file_write_iter+0x536/0x1980 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2066 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x725/0xd60 fs/read_write.c:605
 ksys_write+0x140/0x240 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:667
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f27248d5749
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:00007f2724745038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2724b2bfa0 RCX: 00007f27248d5749
RDX: 0000000000000050 RSI: 0000200000000440 RDI: 0000000000000004
RBP: 00007f2724959f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2724b2c038 R14: 00007f2724b2bfa0 R15: 00007ffcd47638c8

The buggy address belongs to the page:
page:ffffea000435e7c0 refcount:3 mapcount:1 mapping:ffff88811076c6d0 index:0x1 pfn:0x10d79f
aops:def_blk_aops ino:0
flags: 0x400000000002203e(referenced|uptodate|dirty|lru|active|private|mappedtodisk)
raw: 400000000002203e ffffea0004699348 ffffea0004370088 ffff88811076c6d0
raw: 0000000000000001 ffff888121553bd0 0000000300000000 ffff888100140000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888100140000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 306, ts 454070550185, free_ts 454056609993
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 __page_cache_alloc include/linux/pagemap.h:290 [inline]
 page_cache_ra_unbounded+0x2c8/0x7d0 mm/readahead.c:226
 do_page_cache_ra mm/readahead.c:277 [inline]
 force_page_cache_ra+0x3a9/0x400 mm/readahead.c:308
 page_cache_sync_ra+0x237/0x2a0 mm/readahead.c:582
 page_cache_sync_readahead include/linux/pagemap.h:837 [inline]
 generic_file_buffered_read+0x55b/0x2730 mm/filemap.c:2250
 generic_file_read_iter+0x116/0x560 mm/filemap.c:2568
 blkdev_read_iter+0x12f/0x160 fs/block_dev.c:1956
 call_read_iter include/linux/fs.h:2060 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x874/0xa10 fs/read_write.c:496
 ksys_read+0x140/0x240 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:642
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page mm/page_alloc.c:3391 [inline]
 free_the_page mm/page_alloc.c:5429 [inline]
 __free_pages+0x14b/0x380 mm/page_alloc.c:5440
 __free_slab+0xcf/0x190 mm/slub.c:1899
 free_slab mm/slub.c:1914 [inline]
 discard_slab+0x29/0x40 mm/slub.c:1920
 __slab_free+0x313/0x3a0 mm/slub.c:3136
 do_slab_free mm/slub.c:3196 [inline]
 ___cache_free+0x111/0x130 mm/slub.c:3215
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2965
 getname_flags+0xb9/0x500 fs/namei.c:141
 getname+0x19/0x20 fs/namei.c:212
 do_sys_openat2+0xd9/0x6d0 fs/open.c:1213
 do_sys_open fs/open.c:1235 [inline]
 __do_sys_openat fs/open.c:1251 [inline]
 __se_sys_openat fs/open.c:1246 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1246

Memory state around the buggy address:
 ffff88810d79fd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88810d79fe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88810d79fe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                    ^
 ffff88810d79ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88810d79ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop4): ext4_ind_map_blocks:602: inode #15: comm syz.4.1400: Can't allocate blocks for non-extent mapped inodes with bigalloc