From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f79.google.com (mail-oa1-f79.google.com [209.85.160.79]) (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 5DA0C3BFE3D for ; Thu, 8 Jan 2026 13:32:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767879153; cv=none; b=YuNeByhiF9gNtoUIZb8REman3Tr3++WDgDM8c83GfKv0QUdlR3NNf6n82L34sL0OfdeogE4HW1rs8DViBSzNkiIQmOTBaZnjZNb/RGV7svX4vis1X9EgA6X+g54Ba11/b3/XaHS5pPAzqLH28YJ9oJ7UVKtqOKFRcC+F8OXkun8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767879153; c=relaxed/simple; bh=IzERxyI58mINJBE87cDhWytaD0t+dMWpNNhRp/6aIS4=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=MM4sHpuMysfui/zxPny3IcHTnaYksjfygaPE0oA9dU7aQTN++9mqW77YvUs61zZmBNjESvPSoEn4MSwCl7+zwWXAjen7VGq/RyMo0Sxx7AmbEzisCZzD8DoqRkxGgf2dGs7Nlm+uGqRR9mmbp97XXtHPd2RXSKwd9KGNRvTOz5I= 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=209.85.160.79 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-oa1-f79.google.com with SMTP id 586e51a60fabf-3ec31d72794so4558166fac.0 for ; Thu, 08 Jan 2026 05:32:28 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767879145; x=1768483945; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=yxOPx77ojQHMZTvwuZnC5Mc8hnjGrzkIOk9cOBdfj8s=; b=mDhFOVRQuvUtffmVZDeNu96lUqBughe3GL/9kIUx4ldsiQpkcjSaYQUNK1UMY3ZukC 0jpBp9w04psMI8I/pO6MkmU8kHvGDTuvegsI5WecCDCz2WdgJlclc1DmOFKC4knesQuR o035g/pGA7ZrlapYD8PuoR9tFAAitFchignVK05DIjGtb8vaveTInjaD4/9t/GuDzf1x 1XPZIg4dAd3yrXLdBo57CpcQ4Wpn51ZJHJFHvzVmR0WCz6Kp9FeXBaESd/+wHeLqFsCu cxc1NDsaREgz5mnXy5Z/KnUTVZdb2QjnWR0OGImOEOCWHaMtq4cywomdpaw4dChfGsbn TSzA== X-Forwarded-Encrypted: i=1; AJvYcCXtctESfexaMhFOBDxcrN1aGicZAS12xDOs6bzFuwEZhziGgSY+KBcvDZm1LVAI7sSiPJHSxI01lS08E8o=@vger.kernel.org X-Gm-Message-State: AOJu0Ywc256rDpRYkI/oa5Hf8SxtovALeFbCf+GFgOGfBvpJWHzEPS3T FtITZx00+QzAPP5kNqaGCqwmyfEOppowjybbsCbI+S95VBX77eK+CC9xsbrtvzlyoNM0rSicU/Z FIICi+DN6KGtLHE/jT4d0YoyQXnrdLp6reF0XwBu8S4ZJt10kngrYSCKZyRQ= X-Google-Smtp-Source: AGHT+IGaYnIptaDpPlurtpgRwve0LGNo1fZhlNLnl6aSSQsrmE0G02DPXQcZWnQpnudigoz7Dfgk3Y8sGcurbms5da+P6AgIs88R Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:db5a:0:b0:659:9a49:8e17 with SMTP id 006d021491bc7-65f481ba4demr4416699eaf.9.1767879144827; Thu, 08 Jan 2026 05:32:24 -0800 (PST) Date: Thu, 08 Jan 2026 05:32:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <695fb1e8.050a0220.1c677c.039f.GAE@google.com> Subject: [syzbot] [net?] KASAN: slab-use-after-free Read in macvlan_forward_source From: syzbot To: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 94909c53e442 Merge branch 'hsr-send-correct-hsrv0-supervis.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=14e1c914580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9 dashboard link: https://syzkaller.appspot.com/bug?extid=7182fbe91e58602ec1fe compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a204397b7264/disk-94909c53.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/8433b628eb0c/vmlinux-94909c53.xz kernel image: https://storage.googleapis.com/syzbot-assets/8c6d98cf6bab/bzImage-94909c53.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in macvlan_forward_source+0x512/0x630 drivers/net/macvlan.c:436 Read of size 2 at addr ffff888030edadfc by task ksoftirqd/0/15 CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 macvlan_forward_source+0x512/0x630 drivers/net/macvlan.c:436 macvlan_handle_frame+0x2e2/0x12e0 drivers/net/macvlan.c:471 __netif_receive_skb_core+0x10b9/0x4380 net/core/dev.c:5966 __netif_receive_skb_one_core net/core/dev.c:6077 [inline] __netif_receive_skb+0x72/0x380 net/core/dev.c:6192 process_backlog+0x60e/0x14f0 net/core/dev.c:6544 __napi_poll+0xc7/0x360 net/core/dev.c:7594 napi_poll net/core/dev.c:7657 [inline] net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784 handle_softirqs+0x286/0x870 kernel/softirq.c:622 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1063 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 Allocated by task 8954: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5642 [inline] __kvmalloc_node_noprof+0x5cd/0x910 mm/slub.c:7100 alloc_netdev_mqs+0xa6/0x11b0 net/core/dev.c:11900 rtnl_create_link+0x31f/0xd10 net/core/rtnetlink.c:3641 rtnl_newlink_create+0x25c/0xb00 net/core/rtnetlink.c:3823 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16e4/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719 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 8954: 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:2539 [inline] slab_free mm/slub.c:6630 [inline] kfree+0x19a/0x6d0 mm/slub.c:6837 rtnl_newlink_create+0x373/0xb00 net/core/rtnetlink.c:3837 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16e4/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719 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 ffff888030eda000 which belongs to the cache kmalloc-cg-4k of size 4096 The buggy address is located 3580 bytes inside of freed 4096-byte region [ffff888030eda000, ffff888030edb000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30ed8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88807bdef5c1 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801a030500 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000040004 00000000f5000000 ffff88807bdef5c1 head: 00fff00000000040 ffff88801a030500 0000000000000000 dead000000000001 head: 0000000000000000 0000000000040004 00000000f5000000 ffff88807bdef5c1 head: 00fff00000000003 ffffea0000c3b601 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7588, tgid 7586 (syz.3.619), ts 114560949545, free_ts 114289273993 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+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab+0x96/0x350 mm/slub.c:3228 new_slab mm/slub.c:3282 [inline] ___slab_alloc+0xe94/0x18a0 mm/slub.c:4651 __slab_alloc+0x65/0x100 mm/slub.c:4770 __slab_alloc_node mm/slub.c:4846 [inline] slab_alloc_node mm/slub.c:5268 [inline] __do_kmalloc_node mm/slub.c:5641 [inline] __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5654 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] __register_sysctl_table+0x72/0x1340 fs/proc/proc_sysctl.c:1379 __addrconf_sysctl_register+0x328/0x4c0 net/ipv6/addrconf.c:7323 addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7371 ipv6_add_dev+0xd46/0x1370 net/ipv6/addrconf.c:460 addrconf_notify+0x794/0x1010 net/ipv6/addrconf.c:3650 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] register_netdevice+0x1608/0x1ae0 net/core/dev.c:11332 register_vlan_dev+0x39e/0x820 net/8021q/vlan.c:179 page last free pid 89 tgid 89 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906 discard_slab mm/slub.c:3326 [inline] __put_partials+0x146/0x170 mm/slub.c:3872 put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3947 __slab_free+0x2b9/0x390 mm/slub.c:5921 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4970 [inline] slab_alloc_node mm/slub.c:5280 [inline] __kmalloc_cache_noprof+0x36f/0x6f0 mm/slub.c:5758 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [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+0xca1/0x8a30 drivers/net/netdevsim/fib.c:889 nsim_fib_event_work+0x249/0x3b0 drivers/net/netdevsim/fib.c:1493 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 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 Memory state around the buggy address: ffff888030edac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888030edad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888030edad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888030edae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888030edae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- 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