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EXT4-fs warning (device loop0): __ext4fs_dirhash:270: inode #2: comm syz-executor384: Siphash requires key
EXT4-fs warning (device loop0): dx_probe:845: inode #2: comm syz-executor384: Hash code is SIPHASH, but hash not in dirent
EXT4-fs warning (device loop0): dx_probe:966: inode #2: comm syz-executor384: Corrupt directory, running e2fsck is recommended
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BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85
Read of size 2 at addr ffff888123721003 by task syz-executor384/289

CPU: 1 PID: 289 Comm: syz-executor384 Not tainted 6.1.138-syzkaller-00003-g47e5d7e91778 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x71/0x210 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:427
 kasan_report+0x122/0x150 mm/kasan/report.c:531
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:349
 __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85
 ext4_readdir+0x1266/0x3c10 fs/ext4/dir.c:261
 iterate_dir+0x271/0x610 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xe5/0x240 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:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3cc88a1499
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 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:00007fffd7fb3e98 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 6f6972706f695f6c RCX: 00007f3cc88a1499
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fffd7fb3f68 R08: 00007f3cc88ea160 R09: 00007f3cc88ea160
R10: 00007f3cc88ea160 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffd7fb4208 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00048dc840 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x123721
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea00048dc888 ffffea00048cba48 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 277, tgid 277 (sshd-session), ts 24349860188, free_ts 24371354877
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2637
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2644
 get_page_from_freelist+0x2c6e/0x2ce0 mm/page_alloc.c:4539
 __alloc_pages+0x19e/0x3a0 mm/page_alloc.c:5842
 __folio_alloc+0x12/0x40 mm/page_alloc.c:5874
 __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:4283 [inline]
 handle_pte_fault mm/memory.c:5169 [inline]
 __handle_mm_fault mm/memory.c:5313 [inline]
 handle_mm_fault+0x18ef/0x2640 mm/memory.c:5453
 do_user_addr_fault+0x905/0x1050 arch/x86/mm/fault.c:1323
 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:1545 [inline]
 free_pcp_prepare mm/page_alloc.c:1619 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3581
 free_unref_page_list+0xba/0x7c0 mm/page_alloc.c:3729
 release_pages+0xad1/0xb20 mm/swap.c:1043
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:315
 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+0x28d/0x2e0 mm/mmap.c:2402
 do_mas_align_munmap+0xb94/0x11b0 mm/mmap.c:2668
 do_mas_munmap+0x241/0x2b0 mm/mmap.c:2726
 __vm_munmap+0x19f/0x2f0 mm/mmap.c:3025
 __do_sys_munmap mm/mmap.c:3051 [inline]
 __se_sys_munmap mm/mmap.c:3047 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3047
 x64_sys_call+0x8a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888123720f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888123720f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888123721000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888123721080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888123721100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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