From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi2-f4.google.com (mail-oi2-f4.google.com [74.125.231.196]) (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 B134E2F851 for ; Sat, 19 Sep 2026 02:15:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.196 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789784138; cv=none; b=Nb1KLQXwBSS1ZCixnPSe2T4k5s0c7SvCaYPV5ZaC91sq8Vz3LS983HW7I9OumsmgXHGJRTMtt1IWwGxpHIfr1tfaB1yXAfj8Q7T047VbjYGvRIwfKczZ/HW0Rrmux24bHWiiFSdiQNEeJwTIpIH6H+n5oBHVawPIBMDqrUGsaiU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789784138; c=relaxed/simple; bh=Wy8+Pw1gQmFFBV9FC2byyz/R2RAkHytLCIqgfgJNq/8=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=m8fSHgRO6c4GRU+XPw+R2V9dUOEQH2wrj0J+O1lYom0IKUk2uodo8Zt+NdgWUIZpel/ilM22Co8C1XL25hlOmin/8BczjjEde7SUJYSmbxRQRbuFrj+C8ZQkSf4u+N2zJZsmonU9lcUC4czSUQWXrfw2ma9FjCX29Jcr9vk9XFc= 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=74.125.231.196 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-oi2-f4.google.com with SMTP id 5614622812f47-4ab2d8e7e4cso503726b6e.1 for ; Fri, 18 Sep 2026 19:15:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789784135; x=1790388935; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=WcNyjs+p1qdhWL9OvECznb7Rg039M9i00b1BFMLdAOY=; b=ePPAt7bexKe1qdGfuhJoOn0EcjRgrhOt6sKcKf/4oxzT6urTIaOmcajSHERxSA4MZv DjEhwkB/qmkBOdEvD8RhoRXF5KyYMJt/oAYUqIXfB1TtHOSwRUo4pHhX2ur3l1nMfBJA dPdnxXQdaUr678bKiqGrVDVJOv8P2rtKlK4ws5cRDfu1vLG7E0IP3ujFrBUGYhgYhCM6 nhQ1gCA5NVHl0lmZusibo0Un5s0DkdlLURLbT0hIdAEwIrz8aWL0+jjsgShQ3pTSmZpD q9Lg5161oEerzR7K2FMIpCQfQrXMJDreetMcJ/9yjFPt/b2UMbQdhQIN75oS70couL1z 1ZBA== X-Forwarded-Encrypted: i=1; AKwUvBwXs3vfd+e5eJ5ogA7NpU7LzO5cqASTj9rduufg8SpSDbKVcllfJxw2zvB+rjZlva3TqjyGJ6K4qlSWSPg=@vger.kernel.org X-Gm-Message-State: AFuF++kVLjNAVpjKm1CWSU+TJZddjVrnx4kzrQJAQ1oJYO3qg8djoi7H UDMYHkGkpzKks+B/k4Ty6gaAkBHTANK7H3kXxITjR8ppMFe/quILZcjr6lfsQFPjWzsWj5pkjCn PFqEMRdyI/vSIEoxsNPKTfGFecLljNIExvEzUJ4z9jqe/ZIM52Zad7Ac1xaA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2915:b0:6b7:46fa:16af with SMTP id 006d021491bc7-6ca9d14e709mr3706311eaf.68.1789784135476; Fri, 18 Sep 2026 19:15:35 -0700 (PDT) Date: Fri, 18 Sep 2026 19:15:35 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aadf047.71f81b7d.15fa6d.0002.GAE@google.com> Subject: [syzbot] [fs?] KASAN: slab-use-after-free Read in seq_printf From: syzbot To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c3d85c669d09 Merge tag 'ksmbd-for-7.3-rc4' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=134fb7f9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=84649d3ff8d550cb dashboard link: https://syzkaller.appspot.com/bug?extid=bc6b37960b1d13f68f9f compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ca331c4b913d/disk-c3d85c66.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f92fda9de386/vmlinux-c3d85c66.xz kernel image: https://storage.googleapis.com/syzbot-assets/cab83c4f0b39/bzImage-c3d85c66.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bc6b37960b1d13f68f9f@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline] BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730 Read of size 1 at addr ffff88807ec60758 by task syz.2.6295/19648 CPU: 0 UID: 0 PID: 19648 Comm: syz.2.6295 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 string_nocheck lib/vsprintf.c:648 [inline] string+0x471/0x4d0 lib/vsprintf.c:730 vsnprintf+0x422/0x1300 lib/vsprintf.c:2949 seq_vprintf fs/seq_file.c:392 [inline] seq_printf+0x1a4/0x250 fs/seq_file.c:407 input_devices_seq_show+0x1bf/0x1130 drivers/input/input.c:1178 seq_read_iter+0xbce/0x1270 fs/seq_file.c:273 seq_read+0x344/0x4d0 fs/seq_file.c:163 pde_read fs/proc/inode.c:308 [inline] proc_reg_read+0x240/0x330 fs/proc/inode.c:320 vfs_read+0x1e4/0xb40 fs/read_write.c:572 ksys_read+0x12a/0x250 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585059e159 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:00007f5851388028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f5850825fa0 RCX: 00007f585059e159 RDX: 0000000000002020 RSI: 00002000000028c0 RDI: 0000000000000003 RBP: 00007f585063506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5850826038 R14: 00007f5850825fa0 R15: 00007fff7b0fc418 Allocated by task 18319: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_noprof+0x32f/0x840 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2252 sk_alloc+0x36/0xe80 net/core/sock.c:2308 __netlink_create+0x5e/0x2c0 net/netlink/af_netlink.c:627 netlink_create+0x29b/0x610 net/netlink/af_netlink.c:685 __sock_create+0x339/0x860 net/socket.c:1676 sock_create net/socket.c:1734 [inline] __sys_socket_create net/socket.c:1771 [inline] __sys_socket+0x14d/0x260 net/socket.c:1818 __do_sys_socket net/socket.c:1832 [inline] __se_sys_socket net/socket.c:1830 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1830 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5650: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x22b/0x6d0 mm/slub.c:6801 sk_prot_free net/core/sock.c:2291 [inline] __sk_destruct+0x88c/0xab0 net/core/sock.c:2391 sk_destruct+0xc8/0xf0 net/core/sock.c:2419 __sk_free+0xf4/0x3e0 net/core/sock.c:2430 sk_free+0x61/0x90 net/core/sock.c:2441 deferred_put_nlk_sk+0xbe/0x110 net/netlink/af_netlink.c:715 rcu_do_batch kernel/rcu/tree.c:2650 [inline] rcu_core+0x5f0/0x1260 kernel/rcu/tree.c:2919 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0x16a/0x210 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 Last potentially related work creation: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3181 netlink_release+0xb3b/0x2000 net/netlink/af_netlink.c:797 __sock_release+0xb3/0x260 net/socket.c:735 sock_close+0x1c/0x30 net/socket.c:1526 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 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:70 [inline] exit_to_user_mode_loop+0x1d8/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807ec60000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1880 bytes inside of freed 2048-byte region [ffff88807ec60000, ffff88807ec60800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807ec63000 pfn:0x7ec60 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801c035000 ffffea0000ab6010 ffffea000091a410 raw: ffff88807ec63000 0000000000080006 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801c035000 ffffea0000ab6010 ffffea000091a410 head: ffff88807ec63000 0000000000080006 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 13, tgid 13 (kworker/u8:1), ts 67461498561 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7417 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_node_track_caller_noprof+0x6a8/0x870 mm/slub.c:5545 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637 __alloc_skb+0x185/0x710 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] nlmsg_new include/net/netlink.h:1055 [inline] inet6_ifinfo_notify+0x77/0x140 net/ipv6/addrconf.c:6216 addrconf_notify+0xb54/0x1ba0 net/ipv6/addrconf.c:3796 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2275 netif_state_change+0x165/0x380 net/core/dev.c:1625 linkwatch_do_dev net/core/link_watch.c:186 [inline] linkwatch_do_dev+0xe0/0x120 net/core/link_watch.c:166 __linkwatch_run_queue+0x3a9/0x900 net/core/link_watch.c:240 page last free pid 25 tgid 25 ts 67435951267 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __kmalloc_cache_noprof+0x278/0x6d0 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline] nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline] nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline] nsim_fib_event_work+0x1573/0x6330 drivers/net/netdevsim/fib.c:1493 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 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: ffff88807ec60600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ec60680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807ec60700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807ec60780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ec60800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== --- 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