==================================================================
BUG: KASAN: use-after-free in ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1543
Read of size 1 at addr ffff888131690900 by task syz.4.33/404

CPU: 0 PID: 404 Comm: syz.4.33 Not tainted 6.1.93-syzkaller-00002-gd02968a02321 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
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
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1543
 ext4_find_inline_entry+0x4b6/0x5e0 fs/ext4/inline.c:1722
 __ext4_find_entry+0x2b0/0x1af0 fs/ext4/namei.c:1616
 ext4_lookup_entry fs/ext4/namei.c:1771 [inline]
 ext4_lookup+0x176/0x740 fs/ext4/namei.c:1839
 lookup_one_qstr_excl+0x143/0x290 fs/namei.c:1604
 filename_create+0x28e/0x530 fs/namei.c:3878
 do_mkdirat+0xbd/0x450 fs/namei.c:4122
 __do_sys_mkdirat fs/namei.c:4147 [inline]
 __se_sys_mkdirat fs/namei.c:4145 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4145
 x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
 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: 0033:0x7f8eebb7c797
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 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:00007f8eeca22e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f8eeca22ef0 RCX: 00007f8eebb7c797
RDX: 00000000000001ff RSI: 0000000020000080 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000080
R13: 00007f8eeca22eb0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004c5a400 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x131690
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004c5a488 ffffea0004c5a388 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 315, tgid 315 (udevd), ts 23767960642, free_ts 23769551045
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x213/0x220 mm/page_alloc.c:2590
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2597
 get_page_from_freelist+0x27ea/0x2870 mm/page_alloc.c:4425
 __alloc_pages+0x3a1/0x780 mm/page_alloc.c:5714
 __folio_alloc+0x15/0x40 mm/page_alloc.c:5746
 __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+0x2a4/0x690 mm/readahead.c:259
 do_page_cache_ra mm/readahead.c:311 [inline]
 force_page_cache_ra mm/readahead.c:342 [inline]
 page_cache_sync_ra+0x394/0x450 mm/readahead.c:722
 page_cache_sync_readahead include/linux/pagemap.h:1257 [inline]
 filemap_get_pages mm/filemap.c:2660 [inline]
 filemap_read+0x7a9/0x24b0 mm/filemap.c:2754
 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+0x771/0xad0 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:1498 [inline]
 free_pcp_prepare mm/page_alloc.c:1572 [inline]
 free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3498
 free_unref_page_list+0xf1/0x7b0 mm/page_alloc.c:3646
 release_pages+0xf7f/0xfe0 mm/swap.c:1063
 folios_put include/linux/mm.h:1461 [inline]
 folio_batch_move_lru+0x3cf/0x4a0 mm/swap.c:253
 folio_batch_add_and_move mm/swap.c:263 [inline]
 folio_add_lru+0x23c/0x3f0 mm/swap.c:534
 shmem_get_folio_gfp+0x1531/0x24b0 mm/shmem.c:1986
 shmem_get_folio mm/shmem.c:2082 [inline]
 shmem_write_begin+0x164/0x3a0 mm/shmem.c:2570
 generic_perform_write+0x2f9/0x5c0 mm/filemap.c:3844
 __generic_file_write_iter+0x174/0x3a0 mm/filemap.c:3972
 generic_file_write_iter+0xb1/0x310 mm/filemap.c:4004
 call_write_iter include/linux/fs.h:2274 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x902/0xeb0 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
 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 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:
 ffff888131690800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888131690880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888131690900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888131690980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888131690a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop4): ext4_find_dest_de:2112: inode #12: block 7: comm syz.4.33: bad entry in directory: directory entry overrun - offset=0, inode=1793120026, rec_len=34652, size=56 fake=0