From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f80.google.com (mail-ot1-f80.google.com [209.85.210.80]) (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 D4FE43EBF1C for ; Tue, 31 Mar 2026 09:07:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774948052; cv=none; b=oN4PHCHdmfjtSmGtVLVvXD4gxtpmiqpu9UE9Zt8wEjM0REtFnqTWlPm+NUmSgHiei3IGW068FBVdQP9KigC7XcoUA9glyZMz8BbZ19/6ab6LMTBkKHokXbuVlQe/qe+7s5X36pVfURKDobpJXbxjKEHql64RY0HL4UIiH+bV2sQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774948052; c=relaxed/simple; bh=o/gLKcesU6SdbcdN6ox1MFkTP8fw9leYq0pC2BPZAZ0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Wtbab4Rq0K6CSAb36e7JGFLDlyMcbE2Wj4uLf8FHwpmZwHGu2umOAa+6P28Zfoa2JxbiMduwVyN6/VwrU0lIAmsigo0tarRCHa6h0ei/YAF7r2a+vVGCohQVft/MOYOQUdKYV+qiT+UZYUGna8wX3Xl8qf3HY0E4muaxsX+bbmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f80.google.com with SMTP id 46e09a7af769-7d7df10ae0bso14294908a34.0 for ; Tue, 31 Mar 2026 02:07:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774948048; x=1775552848; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=hOwsQnVoC8n4/+8TxunSebpAnP7Vtw3sdM+Rm58tSqc=; b=GVspRidZhr5+TZqbuSRTEeh5vgTXnXjiiB5rpIOCDlqS8GfgWhoQLqNpV4u9KRxqhi g2mU/4c7Rds33cvrgaBLPzshmwqy6eO3HjFQcueZAs5Qg/KvpKT8kbR/kja0EOaHkGhP kuPrngh93Qkd4W5vq6ZHiz5zPMWHDBHIpnoQ0yqeHZW0VfXorm73FRx80JpcjPgkl2zg mVOdNxJx6dYTUNsPnZL1foSuer5AOo2GwkNAgdPExpattqjcZc6J9ahUfVR2pFYuiqBi CG9EzsgqkuuUsKYHieq8pQmTa2IsQUFpQWmcZxOsr52nqTZ1Kqa26ihmCmkmgQr2x8r5 7OXA== X-Forwarded-Encrypted: i=1; AJvYcCXnKrW+rmPl37CdT1SmHQebnrKHf0kAqoOYDCKSiBJeDxQLXt1KsmuLWpSQSk09ehALbbZl7RZPNpfDeuY=@vger.kernel.org X-Gm-Message-State: AOJu0YxEjMiiYWXUlwvkMFM+xdYNT5yaN2u98016O/gEk7uA5GaYSNC2 mqjwTVlryDsYyI+2bZVvM032ahLF877QaKwL/gq2CSWRq9QQYXaU8aO4M+mr2HTP8k5y46eAjx1 mlNaQ94TuM8xzDcyw6JuOj3QwqE1qI30jApDumw5L5J1ENyGLPEnLl85nxN4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4c07:b0:67e:16b4:aa06 with SMTP id 006d021491bc7-67e1863fa15mr8448074eaf.27.1774948048505; Tue, 31 Mar 2026 02:07:28 -0700 (PDT) Date: Tue, 31 Mar 2026 02:07:28 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69cb8ed0.050a0220.183828.0027.GAE@google.com> Subject: [syzbot] [mm?] KASAN: slab-use-after-free Read in madvise_walk_vmas From: syzbot To: Liam.Howlett@oracle.com, akpm@linux-foundation.org, david@kernel.org, jannh@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, syzkaller-bugs@googlegroups.com, vbabka@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: e77a5a5cfe43 Add linux-next specific files for 20260326 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=13640f52580000 kernel config: https://syzkaller.appspot.com/x/.config?x=51ca7cbda5f81780 dashboard link: https://syzkaller.appspot.com/bug?extid=001b9efd14d3e8fac896 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/63883a48e879/disk-e77a5a5c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/cfdff9b548ab/vmlinux-e77a5a5c.xz kernel image: https://storage.googleapis.com/syzbot-assets/f2e4eca37d44/bzImage-e77a5a5c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+001b9efd14d3e8fac896@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in madvise_walk_vmas+0x661/0xae0 mm/madvise.c:1726 Read of size 8 at addr ffff88803322aa08 by task syz.0.3603/14995 CPU: 1 UID: 0 PID: 14995 Comm: syz.0.3603 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 madvise_walk_vmas+0x661/0xae0 mm/madvise.c:1726 madvise_do_behavior+0x386/0x540 mm/madvise.c:1929 do_madvise+0x1fa/0x2e0 mm/madvise.c:2022 __do_sys_madvise mm/madvise.c:2031 [inline] __se_sys_madvise mm/madvise.c:2029 [inline] __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2029 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f8599c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6f8681a028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f6f85c16090 RCX: 00007f6f8599c799 RDX: 0000000000000019 RSI: 0000000008000000 RDI: 0000200000000000 RBP: 00007f6f85a32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f85c16128 R14: 00007f6f85c16090 R15: 00007ffd2a0e3548 Allocated by task 5846: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x8b1/0x1d90 mm/mmap.c:1786 dup_mm kernel/fork.c:1533 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1585 copy_process+0x1efd/0x4430 kernel/fork.c:2260 kernel_clone+0x26d/0x8e0 kernel/fork.c:2709 __do_sys_clone kernel/fork.c:2850 [inline] __se_sys_clone kernel/fork.c:2834 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2834 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15002: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free_after_rcu_debug+0x12a/0x220 mm/slub.c:6304 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 lock_sock include/net/sock.h:1713 [inline] packet_do_bind+0x33/0xe10 net/packet/af_packet.c:3198 __sys_bind_socket net/socket.c:1932 [inline] __sys_bind+0x2e3/0x410 net/socket.c:1963 __do_sys_bind net/socket.c:1968 [inline] __se_sys_bind net/socket.c:1966 [inline] __x64_sys_bind+0x7a/0x90 net/socket.c:1966 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2650 [inline] slab_free mm/slub.c:6242 [inline] kmem_cache_free+0x44f/0x650 mm/slub.c:6369 remove_vma mm/vma.c:473 [inline] vms_complete_munmap_vmas+0x929/0xc60 mm/vma.c:1361 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1604 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1652 do_munmap+0xf9/0x170 mm/mmap.c:1067 mremap_to+0x353/0x880 mm/mremap.c:1448 do_mremap mm/mremap.c:1999 [inline] __do_sys_mremap mm/mremap.c:2055 [inline] __se_sys_mremap+0xe6d/0x11d0 mm/mremap.c:2023 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803322aa00 which belongs to the cache vm_area_struct of size 256 The buggy address is located 8 bytes inside of freed 256-byte region [ffff88803322aa00, ffff88803322ab00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803322adc0 pfn:0x3322a memcg:ffff88803322af01 flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88801c294b40 ffffea0001163f90 ffffea0001dba810 raw: ffff88803322adc0 00000008000c000b 00000000f5000000 ffff88803322af01 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11045, tgid 11045 (syz.0.2085), ts 233915893282, free_ts 233883108694 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3938 __alloc_frozen_pages_noprof+0x233/0x3d0 mm/page_alloc.c:5218 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7247 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4905 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 __split_vma+0x1dc/0xa40 mm/vma.c:516 split_vma mm/vma.c:599 [inline] vma_modify+0x88a/0x1e10 mm/vma.c:1691 vma_modify_flags+0x24b/0x330 mm/vma.c:1719 mprotect_fixup+0x62a/0xb60 mm/mprotect.c:759 do_mprotect_pkey+0x8d5/0xd20 mm/mprotect.c:937 __do_sys_mprotect mm/mprotect.c:958 [inline] __se_sys_mprotect mm/mprotect.c:955 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:955 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 23 tgid 23 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2935 __tlb_remove_table_free mm/mmu_gather.c:228 [inline] tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88803322a900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88803322a980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff88803322aa00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803322aa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803322ab00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup