From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f72.google.com (mail-ot1-f72.google.com [209.85.210.72]) (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 5233E3EBF3E for ; Sat, 14 Feb 2026 10:01:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771063288; cv=none; b=NTt1d8I1ThxC4v6O+AP8Qrp8OK9XiB6ESAObY7hCDA0wskZlfL//wdBvM/1uSxH5TYb4iedp04/AmREUGckzX/Vl7TPVKoj7+H8idev64GPDYDA4Qkw5BJbXITdQk7iDE4VpR125OtgtBsTTeQOJ28Of8cioytxaIFqbXRGoe0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771063288; c=relaxed/simple; bh=JzvvAQDo255Uoa9Wkt+7EbYcAopXLh91XzbMxFg4iTk=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=M1Ys1MPtq2u2JeSpfIngioJkYJAAoaohFoxJ5HZW8Xsay00V4iy97PbhTIdrwyM41iaWdsjrw2LQ5DmsOnOhDUO9hkAhhSWbequSdpDuqG2c1qzZAYBqRU4xQKfdXrlxjNmPRfkJMpnHTFxtviIoShs+iXh4PWMO7D4OKne9Boo= 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=209.85.210.72 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-f72.google.com with SMTP id 46e09a7af769-7d4c1b2651fso6193784a34.3 for ; Sat, 14 Feb 2026 02:01:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771063286; x=1771668086; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=RpJnN0LSuWvQ/aJ10zmSMRns/brlshB95NlgWxlHqWQ=; b=hmX+pWNlcW0R9c9137RLnpUjo2d0VJuPYN+3EcV8/kophcAcvXiE6hmHUlkB3ZdZEZ BGrBEmeuK67D9NJQzk98SRMvRkcIivS6rOHGRI9gpisxMrEV73kXkp+PO+uKUvItF97D x0BIYjSqkmJ2Tb94xtrnbfMSd1PxobY23Nt8Kr8pInav1xQIefCLHN7NVBObzyiJK6Me yVp4IzwFWVpFsS1sziHHFS0cIZwjo+mShbE5h3i2qPC0pVMXq1+1BIcO2gDhVQhZyOaB MGGrn5F1NKgqkg30O5etsGkp80dBp22V1DUmPuFn/NcV3JI4P+etCd/JEVuJ7ngKnVME yvCA== X-Forwarded-Encrypted: i=1; AJvYcCUmnyGYF+HMBB/zPjN6uE2Z58ea3hJZsNqtBmyalEQS3kWQeJfqS4F50DL4npPWDfVG0uXtDBvD4MwYJDg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz4GtbI8/RWfag3Q4Af8ORdGCfkmRJ6QTW4bQBtAV91p52HgVzU QV8TXvaotjMMpT95OUuCRua0/vHOPNnLJ65xL6XSeY/IE3vAQKzMe+Y3nqpqZq1Xs9uE6y5R6ZA RT88F0LDPghnDkq9inxs06eXZpvTnboKS/9OfpDPh7g6tQ5kYDPMPqWOlQXE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1791:b0:66f:4458:67ca with SMTP id 006d021491bc7-6785b1c2611mr1154986eaf.40.1771063286201; Sat, 14 Feb 2026 02:01:26 -0800 (PST) Date: Sat, 14 Feb 2026 02:01:26 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <699047f6.050a0220.2757fb.0024.GAE@google.com> Subject: [syzbot] [fs?] KASAN: slab-use-after-free Read in clone_mnt From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12c6a6e6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e dashboard link: https://syzkaller.appspot.com/bug?extid=a89f9434fb5a001ccd58 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/b33c549157ca/disk-c22e26bd.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/34c7ded19553/vmlinux-c22e26bd.xz kernel image: https://storage.googleapis.com/syzbot-assets/66faec2158ed/bzImage-c22e26bd.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a89f9434fb5a001ccd58@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x4e/0x130 lib/list_debug.c:29 Read of size 8 at addr ffff8880341bcb40 by task syz.6.5169/22925 CPU: 1 UID: 0 PID: 22925 Comm: syz.6.5169 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __list_add_valid_or_report+0x4e/0x130 lib/list_debug.c:29 __list_add_valid include/linux/list.h:96 [inline] __list_add include/linux/list.h:158 [inline] list_add include/linux/list.h:177 [inline] clone_mnt+0x447/0x9a0 fs/namespace.c:1275 copy_tree+0xde/0x930 fs/namespace.c:2159 copy_mnt_ns+0x24d/0x990 fs/namespace.c:4246 create_new_namespaces+0xcf/0x6a0 kernel/nsproxy.c:98 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4f4/0x900 kernel/fork.c:3174 __do_sys_unshare kernel/fork.c:3245 [inline] __se_sys_unshare kernel/fork.c:3243 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3243 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff48d79bf79 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:00007ff48b9f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007ff48da15fa0 RCX: 00007ff48d79bf79 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000002a020400 RBP: 00007ff48d8327e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff48da16038 R14: 00007ff48da15fa0 R15: 00007ffc92e1ac28 Allocated by task 22855: 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:4459 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4795 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 create_new_namespace fs/namespace.c:3098 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0x507/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 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: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:2670 [inline] slab_free mm/slub.c:6082 [inline] kmem_cache_free+0x185/0x690 mm/slub.c:6212 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core kernel/rcu/tree.c:2869 [inline] rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 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:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to 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 task_work_add+0xb6/0x440 kernel/task_work.c:70 mntput_no_expire_slowpath+0x70c/0xbd0 fs/namespace.c:1379 create_new_namespace fs/namespace.c:3162 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0xe17/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880341bca80 which belongs to the cache mnt_cache of size 352 The buggy address is located 192 bytes inside of freed 352-byte region [ffff8880341bca80, ffff8880341bcbe0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880341bda40 pfn:0x341bc head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff8880341bc171 flags: 0x80000000000240(workingset|head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000240 ffff888140412780 ffffea0001036010 ffffea000100bc10 raw: ffff8880341bda40 000001c00012000f 00000000f5000000 ffff8880341bc171 head: 0080000000000240 ffff888140412780 ffffea0001036010 ffffea000100bc10 head: ffff8880341bda40 000001c00012000f 00000000f5000000 ffff8880341bc171 head: 0080000000000001 ffffea0000d06f01 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 18378, tgid 18375 (syz.6.3692), ts 1535437491766, free_ts 1534179924298 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3950 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5245 alloc_slab_page mm/slub.c:3238 [inline] allocate_slab+0x77/0x660 mm/slub.c:3411 new_slab mm/slub.c:3469 [inline] refill_objects+0x334/0x3c0 mm/slub.c:7091 refill_sheaf mm/slub.c:2787 [inline] __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4536 alloc_from_pcs mm/slub.c:4639 [inline] slab_alloc_node mm/slub.c:4773 [inline] kmem_cache_alloc_noprof+0x433/0x680 mm/slub.c:4795 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 copy_tree+0x3d4/0x930 fs/namespace.c:2194 get_detached_copy fs/namespace.c:3044 [inline] open_detached_copy+0x23e/0x5a0 fs/namespace.c:3060 vfs_open_tree+0x490/0x1040 fs/namespace.c:3220 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5166 tgid 5166 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973 __slab_free+0x24f/0x2a0 mm/slub.c:5490 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4459 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4795 alloc_filename fs/namei.c:142 [inline] do_getname+0x2e/0x250 fs/namei.c:182 getname include/linux/fs.h:2512 [inline] class_filename_constructor include/linux/fs.h:2539 [inline] do_sys_openat2+0xca/0x200 fs/open.c:1365 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880341bca00: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ffff8880341bca80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880341bcb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880341bcb80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880341bcc00: 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