EXT4-fs (loop0): mounted filesystem without journal. Opts: jqfmt=vfsold,data_err=abort,debug,noload,mblk_io_submit,commit=0x0000000000000005,init_itable=0x0000000000000601,debug,,errors=continue. Quota mode: none.
EXT4-fs warning (device loop0): dx_probe:833: inode #2: comm syz-executor200: Unrecognised inode hash code 4
EXT4-fs warning (device loop0): dx_probe:966: inode #2: comm syz-executor200: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
Read of size 2 at addr ffff8881246d9003 by task syz-executor200/301

CPU: 1 PID: 301 Comm: syz-executor200 Not tainted 5.15.178-syzkaller-00260-g760764029c6d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106
 print_address_description+0x87/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:444
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307
 __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
 ext4_readdir+0x14ba/0x3960 fs/ext4/dir.c:258
 iterate_dir+0x265/0x600 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 x64_sys_call+0x5ae/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f42b747cf69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc43181e48 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f42b747cf69
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007ffc43181e7c R09: 00007ffc43181e7c
R10: 00007ffc43181e7c R11: 0000000000000246 R12: 00007ffc43181e7c
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007ffc43181eb0
 </TASK>

The buggy address belongs to the page:
page:ffffea000491b640 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1246d9
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea000491b688 ffffea0004917f48 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 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 267, ts 18622576465, free_ts 18645596487
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5780
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 do_anonymous_page mm/memory.c:4066 [inline]
 handle_pte_fault+0xec8/0x28f0 mm/memory.c:4906
 __handle_mm_fault mm/memory.c:-1 [inline]
 do_handle_mm_fault+0x20bc/0x2400 mm/memory.c:5330
 handle_mm_fault include/linux/mm.h:1836 [inline]
 do_user_addr_fault arch/x86/mm/fault.c:1418 [inline]
 handle_page_fault arch/x86/mm/fault.c:1509 [inline]
 exc_page_fault+0x3b5/0x7f0 arch/x86/mm/fault.c:1565
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
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+0x7c8/0x7d0 mm/page_alloc.c:3534
 free_unref_page_list+0x14b/0xa60 mm/page_alloc.c:3671
 release_pages+0x1310/0x1370 mm/swap.c:1009
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:338
 unmap_region+0x304/0x350 mm/mmap.c:2680
 __do_munmap+0x13e4/0x19d0 mm/mmap.c:2913
 __do_sys_brk mm/mmap.c:257 [inline]
 __se_sys_brk+0x403/0x860 mm/mmap.c:196
 __x64_sys_brk+0x38/0x40 mm/mmap.c:196
 x64_sys_call+0x7c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:13
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff8881246d8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881246d8f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881246d9000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8881246d9080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881246d9100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 255: comm syz-executor200: path (unknown): bad entry in directory: rec_len is smaller than minimal - offset=1023, inode=0, rec_len=0, size=1024 fake=0