From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f77.google.com (mail-io1-f77.google.com [209.85.166.77]) (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 64DCA2EB87A for ; Mon, 3 Nov 2025 11:20:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762168842; cv=none; b=HI6oTA47Eqi62qgK4/sH3aedl0Ysfq0eQ31dWV8GkfaFoV394NA5SabAu5K/ANMHGnjvIte11J2FZWKi62Ls6TpDbG7uP+avsvbMx43VGs1n+0nqTDNDdQpe//MzXHzoI7+K9FACGUFcgyvkOoC056QpUI1k4GjEoMpOmQBoda4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762168842; c=relaxed/simple; bh=S/yG6gRhhhzJqWkyNQd+B10jsk7xx+8CBhb9ERcRTOg=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=JppF8nxXUsLBWsoio189f3XfWmkNSCTRcfNigJSVRdKmotRA9IOk5RTBToe2WT3ntG8IFI0VyMMoGHoVYoV8mFegysquBkjTOGaHxjYTGuK7R/TB2MluqSwvSOZ9mvk6k8I/rJksGQ4cs6bQaaMX96q6rS7t/hMCV6rM3ZbmqHc= 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=209.85.166.77 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-io1-f77.google.com with SMTP id ca18e2360f4ac-930db3a16c9so367458239f.0 for ; Mon, 03 Nov 2025 03:20:40 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762168839; x=1762773639; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=qGgUjc8bnDbgLFKyRYg+F31Jn5Kljp1psn7vtHVfqXI=; b=KQSzADgGoyapvGqu+aVs+tvtKRPP1/05uJkoel5rgAxi+O6eXVmmoHzcj74oCXLu3P yekmu749dab+EVsXEp0PWHi6WOOTyXNfxPm86Yi0OwU1ZeQkPDOrNflzeGzuseMQRrF6 b0l2IqxOO9D7Z+yxBqAZvvFWXdcIGJpbn3KAZ94x+RPv7WmRDnPqTLDQL3D9mrR+oRKB 3S0ID7lmGuja7GUYDALwM8zrnl/+AyQohVxyttM+FtBWv1eCueAQeZ3ZphMOdHOLc9ov 7EfwQGFoRLooQT+QaQP/umtCDgCYRfq/IhWXhpRIUxqqfocC45wugFfYVIN8iG47ZWYA Q7eQ== X-Forwarded-Encrypted: i=1; AJvYcCXRqkljLqLvvqK0tDtgZ4hGoTxYWHZmpW9XJ5J8W+0F7Mt3VpT2as/dzlIHG4D/D1bZJkUviPaJrVvk0NQ=@vger.kernel.org X-Gm-Message-State: AOJu0YzsOAavRxbQ6+8aftl25CsNa28uGay7D5j3Hyl5JmquCQ46Vk7Q l0LmbDrE+cHiNfoPNEUFIqmCSUaD59RjTm1WWHLzr0/J9iiS7rG3dFDKHgLjgC1jwxSKtCtJmkS O4/BPpBUsCy6OiOr72jJ7feCE2oe+BBNxvuUoOSc1Ysjxh7u7JE0giDEvmGw= X-Google-Smtp-Source: AGHT+IHTTV/oRqrke/u+oYUWpA+4nE2Nbx5045bcGXRvYb9BEdcZG4INAr4DD7lQCIeyaa/6agoYGZNb82U5KHaGOxrjQVB9YYj4 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:3f81:b0:93e:7f36:a90f with SMTP id ca18e2360f4ac-9482291deefmr1880496439f.3.1762168826765; Mon, 03 Nov 2025 03:20:26 -0800 (PST) Date: Mon, 03 Nov 2025 03:20:26 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69088ffa.050a0220.29fc44.003d.GAE@google.com> Subject: [syzbot] [bridge?] KASAN: slab-use-after-free Read in br_switchdev_fdb_populate From: syzbot To: bridge@lists.linux.dev, davem@davemloft.net, edumazet@google.com, horms@kernel.org, idosch@nvidia.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, razor@blackwall.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: fd57572253bc Merge tag 'sched_ext-for-6.18-rc3-fixes' of g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13f957e2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=609c87dcb0628493 dashboard link: https://syzkaller.appspot.com/bug?extid=dd280197f0f7ab3917be compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a4541b741dd8/disk-fd575722.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/eae4ddf523dd/vmlinux-fd575722.xz kernel image: https://storage.googleapis.com/syzbot-assets/28e03b35c3fc/bzImage-fd575722.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+dd280197f0f7ab3917be@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in br_switchdev_fdb_populate+0x390/0x3a0 net/bridge/br_switchdev.c:141 Read of size 8 at addr ffff888025122808 by task kworker/0:2/977 CPU: 0 UID: 0 PID: 977 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_long br_fdb_cleanup Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 br_switchdev_fdb_populate+0x390/0x3a0 net/bridge/br_switchdev.c:141 br_switchdev_fdb_notify+0x1df/0x2c0 net/bridge/br_switchdev.c:165 fdb_notify+0x16c/0x1a0 net/bridge/br_fdb.c:186 fdb_delete+0x76e/0x12a0 net/bridge/br_fdb.c:324 br_fdb_cleanup+0x43e/0x600 net/bridge/br_fdb.c:574 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5810: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] new_nbp net/bridge/br_if.c:431 [inline] br_add_if+0x41d/0x1b70 net/bridge/br_if.c:599 do_set_master+0x40f/0x730 net/core/rtnetlink.c:2956 do_setlink.constprop.0+0xbd8/0x4380 net/core/rtnetlink.c:3158 rtnl_changelink net/core/rtnetlink.c:3769 [inline] __rtnl_newlink net/core/rtnetlink.c:3928 [inline] rtnl_newlink+0x1446/0x2000 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x4a3/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2247 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15061: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 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+0x5f/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+0x2b8/0x6d0 mm/slub.c:6837 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1e7/0x5a0 lib/kobject.c:737 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x79c/0x1530 kernel/rcu/tree.c:2861 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:559 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3123 br_del_if+0xe0/0x270 net/bridge/br_if.c:740 do_set_master+0x172/0x730 net/core/rtnetlink.c:2940 do_setlink.constprop.0+0xbd8/0x4380 net/core/rtnetlink.c:3158 rtnl_group_changelink net/core/rtnetlink.c:3783 [inline] __rtnl_newlink net/core/rtnetlink.c:3937 [inline] rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2630 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2684 __sys_sendmsg+0x16d/0x220 net/socket.c:2716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888025122800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 8 bytes inside of freed 1024-byte region [ffff888025122800, ffff888025122c00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888025125800 pfn:0x25120 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 ffff88813ffa6dc0 ffffea0001ee1810 ffffea0000c8c210 raw: ffff888025125800 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813ffa6dc0 ffffea0001ee1810 ffffea0000c8c210 head: ffff888025125800 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000944801 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 5807, tgid 5807 (syz-executor), ts 72613372336, free_ts 72596370994 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab mm/slub.c:3228 [inline] new_slab+0x24a/0x360 mm/slub.c:3282 ___slab_alloc+0xdae/0x1a60 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 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+0x501/0x880 mm/slub.c:5654 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] __alloc_workqueue+0x112/0x1810 kernel/workqueue.c:5715 alloc_workqueue_noprof+0xd2/0x200 kernel/workqueue.c:5818 wg_newlink+0x24d/0x780 drivers/net/wireguard/device.c:341 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline] __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 page last free pid 5809 tgid 5809 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 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+0x274/0x780 mm/slub.c:5758 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] kset_create lib/kobject.c:965 [inline] kset_create_and_add+0x4d/0x190 lib/kobject.c:1008 register_queue_kobjects net/core/net-sysfs.c:2106 [inline] netdev_register_kobject+0x1ef/0x3d0 net/core/net-sysfs.c:2362 register_netdevice+0x13dc/0x2270 net/core/dev.c:11294 ipcaif_newlink+0x73/0x2c0 net/caif/chnl_net.c:452 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline] __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x4a3/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2247 Memory state around the buggy address: ffff888025122700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888025122780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888025122800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888025122880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888025122900: 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