==================================================================
BUG: KASAN: use-after-free in dx_insert_block+0xe8/0x260 fs/ext4/namei.c:1387
Read of size 157024 at addr ffff88812e812028 by task syz.9.631/2378

CPU: 1 PID: 2378 Comm: syz.9.631 Not tainted 6.1.124-syzkaller-00004-g1ac09f5c0571 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x158/0x4e0 mm/kasan/report.c:427
 kasan_report+0x13c/0x170 mm/kasan/report.c:531
 kasan_check_range+0x294/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 dx_insert_block+0xe8/0x260 fs/ext4/namei.c:1387
 do_split+0x1e0e/0x2250 fs/ext4/namei.c:2080
 make_indexed_dir+0xeaf/0x1590 fs/ext4/namei.c:2392
 ext4_add_entry+0xbbf/0xed0 fs/ext4/namei.c:2504
 __ext4_link+0x4e9/0x790 fs/ext4/namei.c:3522
 ext4_link+0x1f3/0x290 fs/ext4/namei.c:3563
 vfs_link+0x645/0x7f0 fs/namei.c:4598
 do_linkat+0x34d/0x9f0 fs/namei.c:4669
 __do_sys_link fs/namei.c:4703 [inline]
 __se_sys_link fs/namei.c:4701 [inline]
 __x64_sys_link+0x86/0x90 fs/namei.c:4701
 x64_sys_call+0x282/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f410558cde9
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:00007f4106499038 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007f41057a5fa0 RCX: 00007f410558cde9
RDX: 0000000000000000 RSI: 0000400000000bc0 RDI: 0000400000001240
RBP: 00007f410560e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f41057a5fa0 R15: 00007fff1cb15ee8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004ba0480 refcount:3 mapcount:1 mapping:ffff88810b97ba50 index:0x1 pfn:0x12e812
memcg:ffff888100330000
aops:def_blk_aops ino:700009
flags: 0x460000000032205e(referenced|uptodate|dirty|lru|workingset|private|mappedtodisk|unevictable|mlocked|zone=1)
raw: 460000000032205e dead000000000100 dead000000000001 ffff88810b97ba50
raw: 0000000000000001 ffff88810c78c150 0000000300000000 ffff888100330000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 438, tgid 438 (udevd), ts 235141280217, free_ts 235108247299
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x213/0x220 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2612
 get_page_from_freelist+0x2f41/0x2fc0 mm/page_alloc.c:4477
 __alloc_pages+0x234/0x610 mm/page_alloc.c:5775
 __folio_alloc+0x15/0x40 mm/page_alloc.c:5807
 __folio_alloc_node include/linux/gfp.h:245 [inline]
 folio_alloc include/linux/gfp.h:274 [inline]
 filemap_alloc_folio include/linux/pagemap.h:513 [inline]
 page_cache_ra_unbounded+0x2cb/0x800 mm/readahead.c:260
 do_page_cache_ra mm/readahead.c:312 [inline]
 force_page_cache_ra mm/readahead.c:343 [inline]
 page_cache_sync_ra+0x394/0x450 mm/readahead.c:727
 page_cache_sync_readahead include/linux/pagemap.h:1257 [inline]
 filemap_get_pages mm/filemap.c:2688 [inline]
 filemap_read+0x7fa/0x2600 mm/filemap.c:2783
 blkdev_read_iter+0x3de/0x530 block/fops.c:613
 call_read_iter include/linux/fs.h:2268 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x801/0xae0 fs/read_write.c:470
 ksys_read+0x199/0x2c0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:621
 x64_sys_call+0x28/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1513 [inline]
 free_pcp_prepare mm/page_alloc.c:1587 [inline]
 free_unref_page_prepare+0x9f1/0xa00 mm/page_alloc.c:3526
 free_unref_page_list+0xf1/0x7b0 mm/page_alloc.c:3674
 release_pages+0xef9/0xf50 mm/swap.c:1043
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:315
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1e0/0x3f0 mm/mmu_gather.c:361
 unmap_region+0x2c1/0x310 mm/mmap.c:2402
 do_mas_align_munmap+0xd27/0x13a0 mm/mmap.c:2668
 do_mas_munmap+0x23e/0x2b0 mm/mmap.c:2726
 __vm_munmap+0x263/0x3a0 mm/mmap.c:3025
 __do_sys_munmap mm/mmap.c:3051 [inline]
 __se_sys_munmap mm/mmap.c:3047 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3047
 x64_sys_call+0x75/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88812e812f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812e812f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812e813000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88812e813080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812e813100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop9): ext4_dx_csum_set:531: inode #2: comm syz.9.631: dir seems corrupt?  Run e2fsck -D.