From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D0932F3C0F for ; Wed, 22 Oct 2025 20:03:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761163387; cv=none; b=QjEz63BhOimnLEVT67XcUAGyr0z21NIE+Uu+wGkU5CbGNpGeOf2H09gtc+kFziTXjTRtAieEvVQzcLG3ISWh6PBrnPWRG2Mv6HlGYAwP0bDUo7AO+YoDYB0J1zrCZGmhF+ox2J6hn34xCMRRnSvCpwFQQ4ejL/tw3tZmFecalXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761163387; c=relaxed/simple; bh=ePS0SaalvllTQ+RIgU7nFOq8i/BA4GxG/vufsWvKZZs=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; 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List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:3cc5:b0:430:b6a3:53ae with SMTP id e9e14a558f8ab-430c5307332mr328828435ab.30.1761163384380; Wed, 22 Oct 2025 13:03:04 -0700 (PDT) Date: Wed, 22 Oct 2025 13:03:04 -0700 In-Reply-To: <20251022161344.c0bRW%dmantipov@yandex.ru> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68f93878.a70a0220.3bf6c6.0026.GAE@google.com> Subject: Re: [syzbot] [ocfs2?] KASAN: slab-use-after-free Read in ocfs2_fault From: syzbot To: dmantipov@yandex.ru, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: KASAN: slab-use-after-free Read in ocfs2_fault ocfs2: Mounting device (7,2) on (node local, slot 0) with writeback data mode. ================================================================== BUG: KASAN: slab-use-after-free in ocfs2_fault+0xd3/0x400 fs/ocfs2/mmap.c:41 Read of size 8 at addr ffff88803cc37698 by task syz.2.19/6809 CPU: 0 UID: 0 PID: 6809 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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_fault+0xd3/0x400 fs/ocfs2/mmap.c:41 __do_fault+0x138/0x390 mm/memory.c:5280 do_read_fault mm/memory.c:5698 [inline] do_fault mm/memory.c:5832 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault mm/memory.c:6318 [inline] handle_mm_fault+0x23c6/0x3400 mm/memory.c:6487 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1685/0x2860 mm/gup.c:1428 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860 __mm_populate+0x24c/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3471 [inline] vm_mmap_pgoff+0x38a/0x4d0 mm/util.c:586 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f90113deba9 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:00007f9010a4e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f9011625fa0 RCX: 00007f90113deba9 RDX: 00000000027ffff7 RSI: 0000000000600000 RDI: 0000200000000000 RBP: 00007f9011461e19 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9011626038 R14: 00007f9011625fa0 R15: 00007ffc58dfa518 Allocated by task 6809: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4962 [inline] slab_alloc_node mm/slub.c:5272 [inline] kmem_cache_alloc_noprof+0x181/0x6b0 mm/slub.c:5279 vm_area_alloc+0x24/0x140 mm/vma_init.c:32 __mmap_new_vma mm/vma.c:2461 [inline] __mmap_region mm/vma.c:2670 [inline] mmap_region+0xdd8/0x20f0 mm/vma.c:2740 do_mmap+0xc23/0x10c0 mm/mmap.c:558 vm_mmap_pgoff+0x2a9/0x4d0 mm/util.c:581 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 20: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2530 [inline] slab_free_after_rcu_debug+0x130/0x4e0 mm/slub.c:6677 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core kernel/rcu/tree.c:2861 [inline] rcu_cpu_kthread+0xbf6/0x1b50 kernel/rcu/tree.c:2949 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559 slab_free_hook mm/slub.c:2491 [inline] slab_free mm/slub.c:6619 [inline] kmem_cache_free+0x71f/0x910 mm/slub.c:6729 remove_vma mm/vma.c:468 [inline] vms_complete_munmap_vmas+0x626/0x8a0 mm/vma.c:1293 do_vmi_align_munmap+0x372/0x450 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 __vm_munmap+0x207/0x380 mm/vma.c:3156 __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/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803cc37640 which belongs to the cache vm_area_struct of size 256 The buggy address is located 88 bytes inside of freed 256-byte region [ffff88803cc37640, ffff88803cc37740) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803cc37280 pfn:0x3cc37 memcg:ffff888026bd2301 flags: 0x80000000000200(workingset|node=0|zone=1) page_type: f5(slab) raw: 0080000000000200 ffff888019ebbb40 ffffea0000a12c50 ffffea0000ca25d0 raw: ffff88803cc37280 00000000000c000a 00000000f5000000 ffff888026bd2301 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6101, tgid 6101 (dhcpcd-run-hook), ts 130860016193, free_ts 130849245295 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3046 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3219 new_slab mm/slub.c:3273 [inline] ___slab_alloc+0xb12/0x13f0 mm/slub.c:4643 __kmem_cache_alloc_bulk+0x1c0/0x5a0 mm/slub.c:7383 refill_sheaf mm/slub.c:2624 [inline] __pcs_replace_empty_main+0x301/0x530 mm/slub.c:5032 alloc_from_pcs mm/slub.c:5130 [inline] slab_alloc_node mm/slub.c:5257 [inline] kmem_cache_alloc_noprof+0x45e/0x6b0 mm/slub.c:5279 vm_area_dup+0x2b/0x670 mm/vma_init.c:123 dup_mmap+0x90a/0x1ae0 mm/mmap.c:1780 dup_mm kernel/fork.c:1489 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1541 copy_process+0x1704/0x3ae0 kernel/fork.c:2181 kernel_clone+0x224/0x7c0 kernel/fork.c:2609 __do_sys_clone kernel/fork.c:2750 [inline] __se_sys_clone kernel/fork.c:2734 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 page last free pid 6106 tgid 6106 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906 tlb_batch_list_free mm/mmu_gather.c:159 [inline] tlb_finish_mmu+0x112/0x1d0 mm/mmu_gather.c:500 exit_mmap+0x444/0xb40 mm/mmap.c:1293 __mmput+0xcb/0x3d0 kernel/fork.c:1133 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 __do_sys_exit_group kernel/exit.c:1118 [inline] __se_sys_exit_group kernel/exit.c:1116 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88803cc37580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803cc37600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff88803cc37680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803cc37700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88803cc37780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Tested on: commit: 552c5071 Merge tag 'vfio-v6.18-rc3' of https://github... git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=14c5ce7c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b1620e3721dc97c0 dashboard link: https://syzkaller.appspot.com/bug?extid=a49010a0e8fcdeea075f compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=12524614580000