==================================================================
BUG: KASAN: slab-use-after-free in dx_insert_block+0xd9/0x250 fs/ext4/namei.c:1355
Read of size 157024 at addr ffff88811f0f4028 by task syz.3.19/519

CPU: 1 UID: 0 PID: 519 Comm: syz.3.19 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT 
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:94
 dump_stack_lvl+0x107/0x180 lib/dump_stack.c:120
 print_address_description+0x72/0x220 mm/kasan/report.c:378
 print_report+0x5b/0x80 mm/kasan/report.c:482
 kasan_report+0x15f/0x1a0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
 __asan_memmove+0x2d/0x80 mm/kasan/shadow.c:94
 dx_insert_block+0xd9/0x250 fs/ext4/namei.c:1355
 do_split+0x1978/0x1e50 fs/ext4/namei.c:2017
 make_indexed_dir+0xc3d/0x1200 fs/ext4/namei.c:2328
 ext4_add_entry+0xaa4/0xc20 fs/ext4/namei.c:2435
 __ext4_link+0x498/0x730 fs/ext4/namei.c:3472
 ext4_link+0x1de/0x280 fs/ext4/namei.c:3513
 vfs_link+0x4e7/0x6e0 fs/namei.c:4854
 do_linkat+0x1e5/0x460 fs/namei.c:4924
 __do_sys_link fs/namei.c:4958 [inline]
 __se_sys_link fs/namei.c:4956 [inline]
 __x64_sys_link+0x82/0x90 fs/namei.c:4956
 x64_sys_call+0x12c7/0x2fd0 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x5e/0x160 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7cadb8e969
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:00007f7cae98d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007f7caddb5fa0 RCX: 00007f7cadb8e969
RDX: 0000000000000000 RSI: 0000200000000bc0 RDI: 0000200000001240
RBP: 00007f7cadc10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7caddb5fa0 R15: 00007ffded8e9288
 </TASK>

The buggy address belongs to the physical page:
page: refcount:3 mapcount:1 mapping:ffff888110540be8 index:0x1 pfn:0x11f0f4
memcg:ffff888102a6cd00
aops:def_blk_aops ino:700003 dentry name(?):""
flags: 0x4600000000144a3c(referenced|uptodate|dirty|lru|workingset|owner_2|private|unevictable|mlocked|zone=1)
raw: 4600000000144a3c dead000000000100 dead000000000001 ffff888110540be8
raw: 0000000000000001 ffff88811ce0c690 0000000300000000 ffff888102a6cd00
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 521, tgid 521 (udevd), ts 57782426432, free_ts 57750895325
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x280 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2086/0x2150 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x2b7/0x500 mm/page_alloc.c:5148
 __alloc_pages_noprof mm/page_alloc.c:5182 [inline]
 __folio_alloc_noprof+0x14/0xc0 mm/page_alloc.c:5192
 __folio_alloc_node_noprof include/linux/gfp.h:295 [inline]
 folio_alloc_noprof include/linux/gfp.h:330 [inline]
 filemap_alloc_folio_noprof include/linux/pagemap.h:653 [inline]
 ractl_alloc_folio mm/readahead.c:186 [inline]
 page_cache_ra_unbounded+0x2d8/0x680 mm/readahead.c:270
 do_page_cache_ra mm/readahead.c:327 [inline]
 force_page_cache_ra mm/readahead.c:356 [inline]
 page_cache_sync_ra+0x3b3/0x9c0 mm/readahead.c:572
 filemap_get_pages+0x427/0x17c0 mm/filemap.c:2603
 filemap_read+0x3b2/0xf80 mm/filemap.c:2712
 blkdev_read_iter+0x313/0x450 block/fops.c:849
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x5fd/0xc50 fs/read_write.c:572
 ksys_read+0x13e/0x250 fs/read_write.c:715
 __do_sys_read fs/read_write.c:724 [inline]
 __se_sys_read fs/read_write.c:722 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:722
 x64_sys_call+0x2709/0x2fd0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x5e/0x160 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
page last free pid 470 tgid 470 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xb16/0xbd0 mm/page_alloc.c:2895
 free_frozen_pages+0xb/0x30 mm/page_alloc.c:2933
 __free_slab+0xc5/0x120 mm/slub.c:2724
 rcu_free_slab+0x14/0x30 mm/slub.c:2731
 rcu_do_batch+0x558/0xc50 kernel/rcu/tree.c:2605
 rcu_core+0x55e/0xd70 kernel/rcu/tree.c:2861
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2878
 handle_softirqs+0x18f/0x530 kernel/softirq.c:579
 __do_softirq+0xb/0x12 kernel/softirq.c:613

Memory state around the buggy address:
 ffff88811f0f4f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811f0f4f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811f0f5000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88811f0f5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff88811f0f5100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
==================================================================
EXT4-fs error (device loop3): ext4_dx_csum_set:499: inode #2: comm syz.3.19: dir seems corrupt?  Run e2fsck -D.