==================================================================
BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x10f0/0x1160 fs/ext4/namei.c:1246
Read of size 1 at addr ffff888133b81c67 by task syz-executor/450

CPU: 0 PID: 450 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 ext4_htree_fill_tree+0x10f0/0x1160 fs/ext4/namei.c:1246
 ext4_dx_readdir fs/ext4/dir.c:608 [inline]
 ext4_readdir+0x2f80/0x3e10 fs/ext4/dir.c:145
 iterate_dir+0x271/0x610 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xf2/0x250 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 x64_sys_call+0x15c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc1f33c02b3
Code: c7 c0 e8 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb 9e e8 81 9b fd ff 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 e8 ff ff ff f7 d8
RSP: 002b:00007ffe2d230fd8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000055556ecd0910 RCX: 00007fc1f33c02b3
RDX: 0000000000008000 RSI: 000055556ecd0940 RDI: 0000000000000005
RBP: 000055556ecd0940 R08: 0000000000028701 R09: 0000000000000001
R10: 00007fc1f3594ca0 R11: 0000000000000293 R12: 000055556ecd0914
R13: ffffffffffffffe8 R14: 0000000000000010 R15: 00007ffe2d233280
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004cee040 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x133b81
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004cee288 ffffea0004cee088 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 0x8140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO|__GFP_CMA), pid 402, tgid 402 (udevd), ts 48315039456, free_ts 48316020793
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2670
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2677
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4583
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5924
 __folio_alloc+0x12/0x40 mm/page_alloc.c:5957
 __folio_alloc_node include/linux/gfp.h:245 [inline]
 folio_alloc include/linux/gfp.h:274 [inline]
 alloc_page_vma include/linux/gfp.h:283 [inline]
 do_anonymous_page mm/memory.c:4286 [inline]
 handle_pte_fault mm/memory.c:5181 [inline]
 __handle_mm_fault mm/memory.c:5325 [inline]
 handle_mm_fault+0x1972/0x26c0 mm/memory.c:5465
 do_user_addr_fault+0x63b/0x1050 arch/x86/mm/fault.c:1372
 handle_page_fault arch/x86/mm/fault.c:1464 [inline]
 exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1517
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1578 [inline]
 free_pcp_prepare mm/page_alloc.c:1652 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3618
 free_unref_page_list+0x117/0x8c0 mm/page_alloc.c:3769
 release_pages+0xaf2/0xb50 mm/swap.c:1048
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:316
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1aa/0x370 mm/mmu_gather.c:361
 unmap_region+0x2b7/0x320 mm/mmap.c:2419
 do_mas_align_munmap+0xbed/0x1320 mm/mmap.c:2693
 do_mas_munmap+0x241/0x2b0 mm/mmap.c:2751
 __vm_munmap+0x1bd/0x330 mm/mmap.c:3050
 __do_sys_munmap mm/mmap.c:3076 [inline]
 __se_sys_munmap mm/mmap.c:3072 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3072
 x64_sys_call+0x8a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888133b81b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888133b81b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888133b81c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff888133b81c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888133b81d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs (loop1): unmounting filesystem.