EXT4-fs warning (device loop1): dx_probe:892: inode #2: comm syz-executor.1: dx entry: limit 0 != root limit 124
EXT4-fs warning (device loop1): dx_probe:965: inode #2: comm syz-executor.1: Corrupt directory, running e2fsck is recommended
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BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x6f3/0x870 fs/ext4/dir.c:85
Read of size 2 at addr ffff8880645fb003 by task syz-executor.1/5241

CPU: 1 PID: 5241 Comm: syz-executor.1 Not tainted 6.1.92-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 __ext4_check_dir_entry+0x6f3/0x870 fs/ext4/dir.c:85
 ext4_readdir+0x139e/0x3950 fs/ext4/dir.c:258
 iterate_dir+0x224/0x560
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd89747cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd89826c0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fd8975b3fa0 RCX: 00007fd89747cee9
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007fd8974c947f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fd8975b3fa0 R15: 00007fffd27cfdd8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001917ec0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x645fb
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001914108 ffffea00019142c8 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 5215, tgid 5212 (syz-executor.1), ts 161372454342, free_ts 162124971285
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513
 prep_new_page mm/page_alloc.c:2520 [inline]
 get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5547
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5579
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 do_anonymous_page mm/memory.c:4172 [inline]
 handle_pte_fault mm/memory.c:5011 [inline]
 __handle_mm_fault mm/memory.c:5155 [inline]
 handle_mm_fault+0x2e90/0x5340 mm/memory.c:5276
 do_user_addr_fault arch/x86/mm/fault.c:1371 [inline]
 handle_page_fault arch/x86/mm/fault.c:1462 [inline]
 exc_page_fault+0x26f/0x660 arch/x86/mm/fault.c:1518
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1440 [inline]
 free_pcp_prepare mm/page_alloc.c:1490 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3499
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
 unmap_region+0x29f/0x2f0 mm/mmap.c:2332
 do_mas_align_munmap+0xec8/0x15f0 mm/mmap.c:2582
 do_mas_munmap+0x246/0x2b0 mm/mmap.c:2640
 __vm_munmap+0x268/0x370 mm/mmap.c:2917
 __do_sys_munmap mm/mmap.c:2942 [inline]
 __se_sys_munmap mm/mmap.c:2939 [inline]
 __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2939
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff8880645faf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880645faf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880645fb000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880645fb080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880645fb100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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