==================================================================
BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x10f0/0x1160 fs/ext4/namei.c:1246
Read of size 1 at addr ffff88811e965c67 by task syz-executor/472

CPU: 0 PID: 472 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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: 0033:0x7fe886fc02b3
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:00007ffd2d64c238 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000555570610910 RCX: 00007fe886fc02b3
RDX: 0000000000008000 RSI: 0000555570610940 RDI: 0000000000000005
RBP: 0000555570610940 R08: 0000000000028701 R09: 0000000000000001
R10: 00007fe887194ca0 R11: 0000000000000293 R12: 0000555570610914
R13: ffffffffffffffe8 R14: 0000000000000010 R15: 00007ffd2d64e4e0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00047a5940 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11e965
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea000478e148 ffff8881f6e3c858 0000000000000000
raw: 0000000000000000 00000000002a0000 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 164, tgid 164 (dhcpcd-run-hook), ts 7734459258, free_ts 52812044480
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4554
 __alloc_pages+0x1d9/0x480 mm/page_alloc.c:5868
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3d0 mm/slub.c:2020
 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x1b0/0x330 mm/slub.c:3408
 anon_vma_chain_alloc mm/rmap.c:145 [inline]
 __anon_vma_prepare+0x51/0x420 mm/rmap.c:199
 vmf_anon_prepare mm/memory.c:3163 [inline]
 do_cow_fault mm/memory.c:4757 [inline]
 do_fault+0x134e/0x1e20 mm/memory.c:4877
 handle_pte_fault mm/memory.c:5171 [inline]
 __handle_mm_fault mm/memory.c:5313 [inline]
 handle_mm_fault+0x133a/0x26c0 mm/memory.c:5453
 do_user_addr_fault+0x63b/0x1050 arch/x86/mm/fault.c:1374
 handle_page_fault arch/x86/mm/fault.c:1466 [inline]
 exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1522
 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:1551 [inline]
 free_pcp_prepare mm/page_alloc.c:1625 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589
 free_unref_page+0x95/0x540 mm/page_alloc.c:3687
 free_the_page mm/page_alloc.c:836 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:5957
 __free_slab+0xca/0x1a0 mm/slub.c:2044
 free_slab mm/slub.c:2059 [inline]
 discard_slab+0x29/0x40 mm/slub.c:2065
 __slab_free+0x201/0x280 mm/slub.c:3625
 do_slab_free mm/slub.c:3666 [inline]
 ___cache_free+0xbf/0xd0 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x16e/0x330 mm/slub.c:3408
 getname_flags+0xb9/0x500 fs/namei.c:139
 vfs_fstatat fs/stat.c:266 [inline]
 __do_sys_newfstatat fs/stat.c:437 [inline]
 __se_sys_newfstatat+0x127/0x440 fs/stat.c:431
 __x64_sys_newfstatat+0x9b/0xb0 fs/stat.c:431
 x64_sys_call+0x77c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:263

Memory state around the buggy address:
 ffff88811e965b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88811e965b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88811e965c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff88811e965c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88811e965d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs (loop4): unmounting filesystem.