syzbot

loop0: detected capacity change from 0 to 32768
ocfs2: Mounting device (7,0) on (node local, slot 0) with writeback data [  135.179891][ T6055] ocfs2: Mounting device (7,0) on (node local, slot 0) with writeback data mode.
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BUG: KASAN: use-after-free in ocfs2_check_dir_entry fs/ocfs2/dir.c:305 [inline]
BUG: KASAN: use-after-free in ocfs2_dir_foreach_blk_id fs/ocfs2/dir.c:1805 [inline]
BUG: KASAN: use-after-free in ocfs2_dir_foreach_blk+0x1501/0x18a0 fs/ocfs2/dir.c:1933
Read of size 2 at addr ffff888051484cf0 by task syz.0.25/6055

CPU: 0 UID: 0 PID: 6055 Comm: syz.0.25 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 ocfs2_check_dir_entry fs/ocfs2/dir.c:305 [inline]
 ocfs2_dir_foreach_blk_id fs/ocfs2/dir.c:1805 [inline]
 ocfs2_dir_foreach_blk+0x1501/0x18a0 fs/ocfs2/dir.c:1933
 ocfs2_readdir+0x260/0x4d0 fs/ocfs2/dir.c:1977
 wrap_directory_iterator+0x99/0xe0 fs/readdir.c:65
 iterate_dir+0x3a5/0x580 fs/readdir.c:108
 __do_sys_getdents fs/readdir.c:326 [inline]
 __se_sys_getdents+0xe4/0x250 fs/readdir.c:312
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb02435eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd25c00148 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007fb0245a5fa0 RCX: 00007fb02435eba9
RDX: 0000000000000054 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fb0243e1e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb0245a5fa0 R14: 00007fb0245a5fa0 R15: 0000000000000003
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f6d7e2d4 pfn:0x51484
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 ffffea0001452148 ffffea00014520c8 0000000000000000
raw: 00000007f6d7e2d4 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_ZERO|__GFP_COMP), pid 5842, tgid 5842 (syz-executor), ts 104017277507, free_ts 105163598569
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
 vma_alloc_folio_noprof+0xe4/0x280 mm/mempolicy.c:2470
 folio_prealloc+0x30/0x180 mm/memory.c:-1
 alloc_anon_folio mm/memory.c:4997 [inline]
 do_anonymous_page mm/memory.c:5054 [inline]
 do_pte_missing mm/memory.c:4232 [inline]
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault mm/memory.c:6195 [inline]
 handle_mm_fault+0x12ee/0x3400 mm/memory.c:6364
 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
page last free pid 5842 tgid 5842 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 free_unref_folios+0xd66/0x1460 mm/page_alloc.c:2952
 folios_put_refs+0x569/0x670 mm/swap.c:999
 free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:264
 __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:397 [inline]
 tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235
 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277
 do_vmi_align_munmap+0x369/0x440 mm/vma.c:1536
 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584
 __vm_munmap+0x23b/0x3d0 mm/vma.c:3155
 __do_sys_munmap mm/mmap.c:1080 [inline]
 __se_sys_munmap mm/mmap.c:1077 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888051484b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888051484c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888051484c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                             ^
 ffff888051484d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888051484d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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