==================================================================
BUG: KASAN: use-after-free in dx_insert_block fs/ext4/namei.c:1387 [inline]
BUG: KASAN: use-after-free in do_split+0x1a78/0x1f70 fs/ext4/namei.c:2080
Read of size 157024 at addr ffff88811b5ab028 by task syz.8.351/2198

CPU: 1 PID: 2198 Comm: syz.8.351 Not tainted syzkaller #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
 dx_insert_block fs/ext4/namei.c:1387 [inline]
 do_split+0x1a78/0x1f70 fs/ext4/namei.c:2080
 make_indexed_dir+0xe01/0x14a0 fs/ext4/namei.c:2392
 ext4_add_entry+0xc24/0xf40 fs/ext4/namei.c:2504
 __ext4_link+0x4d7/0x770 fs/ext4/namei.c:3536
 ext4_link+0x1de/0x270 fs/ext4/namei.c:3577
 vfs_link+0x636/0x7f0 fs/namei.c:4557
 do_linkat+0x1e7/0x730 fs/namei.c:4628
 __do_sys_link fs/namei.c:4662 [inline]
 __se_sys_link fs/namei.c:4660 [inline]
 __x64_sys_link+0x86/0x90 fs/namei.c:4660
 x64_sys_call+0x34d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:87
 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: 0033:0x7fed36e1b169
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:00007fed3688d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007fed37033fa0 RCX: 00007fed36e1b169
RDX: 0000000000000000 RSI: 0000400000000bc0 RDI: 0000400000001240
RBP: 00007fed36e9c2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fed37033fa0 R15: 00007ffccecb3b68
 </TASK>

The buggy address belongs to the page:
page:ffffea00046d6ac0 refcount:3 mapcount:1 mapping:ffff88810930cb98 index:0x1 pfn:0x11b5ab
memcg:ffff888100256780
aops:def_blk_aops ino:700008
flags: 0x400000000032201e(referenced|uptodate|dirty|lru|private|mappedtodisk|unevictable|mlocked|zone=1)
raw: 400000000032201e ffff88810025bbc0 ffffea000478f248 ffff88810930cb98
raw: 0000000000000001 ffff888120914000 0000000300000000 ffff888100256780
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 414, ts 157898515451, free_ts 157898318765
 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]
 page_cache_ra_unbounded+0x2b2/0x980 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+0x2ae/0x420 mm/readahead.c:590
 page_cache_sync_readahead include/linux/pagemap.h:831 [inline]
 filemap_get_pages mm/filemap.c:2568 [inline]
 filemap_read+0x63a/0x1f70 mm/filemap.c:2653
 generic_file_read_iter+0xac/0x400 mm/filemap.c:2813
 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+0x68b/0xbe0 fs/read_write.c:485
 ksys_read+0x140/0x240 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+0xa2/0x550 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5871
 free_pages+0x82/0x90 mm/page_alloc.c:5882
 ext4_calculate_overhead+0x1071/0x1260 fs/ext4/super.c:3819
 ext4_fill_super+0x6e79/0x9030 fs/ext4/super.c:4808
 mount_bdev+0x2ae/0x3e0 fs/super.c:1400
 ext4_mount+0x34/0x40 fs/ext4/super.c:6621
 legacy_get_tree+0xed/0x190 fs/fs_context.c:611
 vfs_get_tree+0x89/0x260 fs/super.c:1530
 do_new_mount+0x25a/0xa20 fs/namespace.c:3014
 path_mount+0x675/0x1020 fs/namespace.c:3344
 do_mount fs/namespace.c:3357 [inline]
 __do_sys_mount fs/namespace.c:3565 [inline]
 __se_sys_mount+0x318/0x380 fs/namespace.c:3542
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3542
 x64_sys_call+0x6bf/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80

Memory state around the buggy address:
 ffff88811b5abf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811b5abf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811b5ac000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88811b5ac080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88811b5ac100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
EXT4-fs error (device loop8): ext4_dx_csum_set:531: inode #2: comm syz.8.351: dir seems corrupt?  Run e2fsck -D.