EXT4-fs warning (device loop0): dx_probe:833: inode #2: comm syz-executor202: Unrecognised inode hash code 4
EXT4-fs warning (device loop0): dx_probe:966: inode #2: comm syz-executor202: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x6fd/0x880 fs/ext4/dir.c:85
Read of size 2 at addr ffff8880125f1003 by task syz-executor202/5218

CPU: 1 UID: 0 PID: 5218 Comm: syz-executor202 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 __ext4_check_dir_entry+0x6fd/0x880 fs/ext4/dir.c:85
 ext4_readdir+0x1436/0x3a60 fs/ext4/dir.c:259
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:407 [inline]
 __se_sys_getdents64+0x1d3/0x4a0 fs/readdir.c:392
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0e91457c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 1b 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:00007ffe4f6bc318 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007ffe4f6bc430 RCX: 00007fc0e91457c9
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007ffe4f6bc438 R08: 00007fc0e9188258 R09: 00007fc0e9188258
R10: 00007fc0e9188258 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc0e91b96c0 R15: 000000000000001d
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f0e84a87 pfn:0x125f1
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0000476408 ffff8880b8644af0 0000000000000000
raw: 00000007f0e84a87 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 5207, tgid 5207 (sshd), ts 71056529663, free_ts 71161620783
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1545 [inline]
 get_page_from_freelist+0x3039/0x3180 mm/page_alloc.c:3457
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4733
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
 folio_alloc_mpol_noprof mm/mempolicy.c:2283 [inline]
 vma_alloc_folio_noprof+0x12e/0x230 mm/mempolicy.c:2314
 folio_prealloc+0x31/0x170
 alloc_anon_folio mm/memory.c:4721 [inline]
 do_anonymous_page mm/memory.c:4778 [inline]
 do_pte_missing mm/memory.c:3963 [inline]
 handle_pte_fault+0x24dd/0x6800 mm/memory.c:5751
 __handle_mm_fault mm/memory.c:5894 [inline]
 handle_mm_fault+0x1053/0x1ad0 mm/memory.c:6062
 do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
page last free pid 5207 tgid 5207 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1108 [inline]
 free_unref_folios+0xee2/0x18a0 mm/page_alloc.c:2686
 folios_put_refs+0x76c/0x860 mm/swap.c:1007
 free_pages_and_swap_cache+0x2ea/0x690 mm/swap_state.c:332
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
 vms_clear_ptes+0x437/0x530 mm/vma.c:1096
 vms_complete_munmap_vmas+0x208/0x910 mm/vma.c:1140
 do_vmi_align_munmap+0x613/0x730 mm/vma.c:1349
 do_vmi_munmap+0x24e/0x2d0 mm/vma.c:1397
 __vm_munmap+0x24c/0x480 mm/mmap.c:1600
 __do_sys_munmap mm/mmap.c:1617 [inline]
 __se_sys_munmap mm/mmap.c:1614 [inline]
 __x64_sys_munmap+0x68/0x80 mm/mmap.c:1614
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880125f0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880125f0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880125f1000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880125f1080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880125f1100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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