loop0: detected capacity change from 0 to 512
EXT4-fs: Ignoring removed bh option
EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
==================================================================
BUG: KASAN: use-after-free in ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1523
Read of size 1 at addr ffff888126346d23 by task syz-executor.0/451

CPU: 1 PID: 451 Comm: syz-executor.0 Not tainted 6.1.25-syzkaller-00071-gb1644a0031cf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
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:284 [inline]
 print_report+0x158/0x4e0 mm/kasan/report.c:395
 kasan_report+0x13c/0x170 mm/kasan/report.c:495
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1523
 ext4_find_inline_entry+0x4b6/0x5e0 fs/ext4/inline.c:1711
 __ext4_find_entry+0x2b0/0x1af0 fs/ext4/namei.c:1596
 ext4_lookup_entry fs/ext4/namei.c:1751 [inline]
 ext4_lookup+0x176/0x740 fs/ext4/namei.c:1819
 lookup_open fs/namei.c:3391 [inline]
 open_last_lookups fs/namei.c:3481 [inline]
 path_openat+0x10fd/0x2d60 fs/namei.c:3711
 do_filp_open+0x230/0x480 fs/namei.c:3741
 do_sys_openat2+0x13b/0x500 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_creat fs/open.c:1402 [inline]
 __se_sys_creat fs/open.c:1396 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1396
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8a2127cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8a2206c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f8a2139bf80 RCX: 00007f8a2127cae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000e00
RBP: 00007f8a212c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f8a2139bf80 R15: 00007ffda7035f68
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000498d180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x126346
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea000498d1c8 ffffea000498d148 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 451, tgid 450 (syz-executor.0), ts 42677943912, free_ts 42679712195
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e2/0x1f0 mm/page_alloc.c:2533
 prep_new_page mm/page_alloc.c:2540 [inline]
 get_page_from_freelist+0x2e7a/0x2f50 mm/page_alloc.c:4292
 __alloc_pages+0x3c2/0x7d0 mm/page_alloc.c:5559
 __folio_alloc+0x15/0x40 mm/page_alloc.c:5591
 __folio_alloc_node include/linux/gfp.h:246 [inline]
 folio_alloc include/linux/gfp.h:275 [inline]
 shmem_alloc_folio mm/shmem.c:1570 [inline]
 shmem_alloc_and_acct_folio+0x48c/0x920 mm/shmem.c:1594
 shmem_get_folio_gfp+0x12cc/0x24a0 mm/shmem.c:1922
 shmem_get_folio mm/shmem.c:2053 [inline]
 shmem_write_begin+0x164/0x3a0 mm/shmem.c:2540
 generic_perform_write+0x2f9/0x5c0 mm/filemap.c:3754
 __generic_file_write_iter+0x174/0x3a0 mm/filemap.c:3882
 generic_file_write_iter+0xb1/0x310 mm/filemap.c:3914
 call_write_iter include/linux/fs.h:2205 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x893/0xe30 fs/read_write.c:584
 ksys_write+0x199/0x2c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1460 [inline]
 free_pcp_prepare mm/page_alloc.c:1533 [inline]
 free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3388
 free_unref_page_list+0xf6/0x6c0 mm/page_alloc.c:3530
 release_pages+0xf7f/0xfe0 mm/swap.c:1055
 __pagevec_release+0x84/0x100 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x609/0x15a0 mm/shmem.c:944
 shmem_truncate_range mm/shmem.c:1043 [inline]
 shmem_evict_inode+0x25f/0xa30 mm/shmem.c:1152
 evict+0x2a3/0x630 fs/inode.c:664
 iput_final fs/inode.c:1747 [inline]
 iput+0x642/0x870 fs/inode.c:1773
 dentry_unlink_inode+0x34f/0x440 fs/dcache.c:401
 __dentry_kill+0x447/0x650 fs/dcache.c:607
 dentry_kill+0xc0/0x2a0
 dput+0x160/0x310 fs/dcache.c:913
 __fput+0x5ed/0x870 fs/file_table.c:328
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x24d/0x2e0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x8b/0xa0 kernel/entry/common.c:171

Memory state around the buggy address:
 ffff888126346c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888126346c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888126346d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888126346d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888126346e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_find_dest_de:2092: inode #12: block 7: comm syz-executor.0: bad entry in directory: rec_len % 4 != 0 - offset=0, inode=3089191003, rec_len=43069, size=56 fake=0