EXT4-fs warning (device loop2): dx_probe:966: inode #2: comm syz.2.16: 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 ffff88812471c003 by task syz.2.16/559

CPU: 0 PID: 559 Comm: syz.2.16 Not tainted 5.15.178-syzkaller-00235-gcf30300a216a #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+0x87/0x3a0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x177/0x1c0 mm/kasan/report.c:451
 __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: 0033:0x7f831110c169
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:00007f8310b7e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f8311324fa0 RCX: 00007f831110c169
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f831118d2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8311324fa0 R15: 00007ffcad3053e8
 </TASK>

The buggy address belongs to the page:
page:ffffea000491c700 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12471c
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea000491c748 ffff8881f703be20 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 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 534, ts 55135236418, free_ts 55512011913
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x15d/0x170 mm/page_alloc.c:2420
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x3bb6/0x3c90 mm/page_alloc.c:4192
 __alloc_pages+0x38a/0x7b0 mm/page_alloc.c:5465
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 alloc_pages_node include/linux/gfp.h:584 [inline]
 alloc_pages include/linux/gfp.h:597 [inline]
 do_cow_fault mm/memory.c:4281 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4648 [inline]
 __handle_mm_fault mm/memory.c:4783 [inline]
 handle_mm_fault+0x1fbd/0x4350 mm/memory.c:4881
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x23a/0x5e0 arch/x86/mm/fault.c:1501
 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:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1413 [inline]
 free_unref_page_prepare+0x7a9/0x7e0 mm/page_alloc.c:3317
 free_unref_page_list+0x1aa/0x6d0 mm/page_alloc.c:3433
 release_pages+0xe33/0xe90 mm/swap.c:963
 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
 exit_mmap+0x3fe/0x630 mm/mmap.c:3206
 __mmput+0x95/0x300 kernel/fork.c:1127
 mmput+0x59/0x70 kernel/fork.c:1148
 exit_mm kernel/exit.c:550 [inline]
 do_exit+0xb6a/0x29e0 kernel/exit.c:861
 do_group_exit+0x141/0x310 kernel/exit.c:996
 get_signal+0x797/0x1620 kernel/signal.c:2900
 arch_do_signal_or_restart+0xbd/0x1680 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0xa0/0xe0 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x26/0x160 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff88812471bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812471bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812471c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88812471c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812471c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop2): ext4_readdir:260: inode #2: block 255: comm syz.2.16: path (unknown): bad entry in directory: rec_len is smaller than minimal - offset=1023, inode=0, rec_len=0, size=1024 fake=0