================================================================== BUG: KASAN: use-after-free in ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1447 [inline] BUG: KASAN: use-after-free in ocfs2_claim_suballoc_bits+0x8b2/0x2450 fs/ocfs2/suballoc.c:1996 Read of size 4 at addr ffff888076e9d000 by task syz.0.86/6313 CPU: 0 UID: 0 PID: 6313 Comm: syz.0.86 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: 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_find_victim_chain fs/ocfs2/suballoc.c:1447 [inline] ocfs2_claim_suballoc_bits+0x8b2/0x2450 fs/ocfs2/suballoc.c:1996 ocfs2_claim_metadata+0x178/0x4c0 fs/ocfs2/suballoc.c:2082 ocfs2_dx_dir_attach_index+0x1c1/0xd90 fs/ocfs2/dir.c:2333 ocfs2_expand_inline_dir fs/ocfs2/dir.c:3025 [inline] ocfs2_extend_dir+0x3994/0x4870 fs/ocfs2/dir.c:3207 ocfs2_prepare_dir_for_insert+0x2fe8/0x5450 fs/ocfs2/dir.c:4312 ocfs2_symlink+0xaa4/0x23e0 fs/ocfs2/namei.c:1875 vfs_symlink+0x143/0x2f0 fs/namei.c:4730 do_symlinkat+0x1b1/0x3f0 fs/namei.c:4756 __do_sys_symlink fs/namei.c:4777 [inline] __se_sys_symlink fs/namei.c:4775 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4775 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: 0033:0x7f178798eec9 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:00007f178874c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007f1787be5fa0 RCX: 00007f178798eec9 RDX: 0000000000000000 RSI: 0000200000000cc0 RDI: 00002000000003c0 RBP: 00007f1787a11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1787be6038 R14: 00007f1787be5fa0 R15: 00007ffdc4f3f6f8 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2000000ce pfn:0x76e9d flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea0001dba788 ffffea00014c2148 0000000000000000 raw: 00000002000000ce 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 6170, tgid 6168 (syz.0.55), ts 118121155600, free_ts 123179818714 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+0x21e4/0x22c0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline] vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470 folio_prealloc+0x30/0x180 mm/memory.c:-1 wp_page_copy mm/memory.c:3552 [inline] do_wp_page+0x1231/0x5800 mm/memory.c:4013 handle_pte_fault mm/memory.c:6068 [inline] __handle_mm_fault+0x1033/0x5440 mm/memory.c:6195 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364 do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387 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 6170 tgid 6168 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xdbd/0x1520 mm/page_alloc.c:2952 folios_put_refs+0x559/0x640 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 zap_pte_range mm/memory.c:1765 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0x3b31/0x4370 mm/memory.c:1889 unmap_single_vma mm/memory.c:1932 [inline] unmap_vmas+0x399/0x580 mm/memory.c:1976 exit_mmap+0x248/0xb50 mm/mmap.c:1280 __mmput+0x118/0x430 kernel/fork.c:1129 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:949 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888076e9cf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888076e9cf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888076e9d000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888076e9d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888076e9d100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================