WARNING in rtmsg_ifinfo_build_skb

Status: upstream: reported C repro on 2026/08/14 15:33
Subsystems: net
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+f2f6312ad1b5a0bfe316@syzkaller.appspotmail.com
Fix commit: c2de369c5c5b macsec: initialize SecY before registering the netdevice
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci2-upstream-usb]
First crash: 63d, last: 4d06h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
2ea2e14f assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in rtmsg_ifinfo_build_skb 2026/07/31 01:07 2026/07/31 01:07 2026/07/31 01:43 aaffb173
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[PATCH net v3] macsec: initialize SecY before registering the netdevice 3 (3) 2026/09/24 13:21
[PATCH net v2] macsec: initialize SecY before registering the netdevice 3 (3) 2026/09/21 20:43
[PATCH net] macsec: initialize SecY before registering the netdevice 4 (4) 2026/09/18 19:35
Re: [syzbot] [net?] WARNING in rtmsg_ifinfo_build_skb 4 (5) 2026/08/19 08:06
[syzbot] [net?] WARNING in rtmsg_ifinfo_build_skb 0 (1) 2026/08/14 15:33
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/14 15:35 0m edumazet@google.com patch upstream error job log

Sample crash report:
------------[ cut here ]------------
err == -EMSGSIZE
WARNING: net/core/rtnetlink.c:4538 at rtmsg_ifinfo_build_skb+0x1c1/0x260 net/core/rtnetlink.c:4538, CPU#1: syz.0.17/5924
Modules linked in:
CPU: 1 UID: 0 PID: 5924 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:rtmsg_ifinfo_build_skb+0x1c1/0x260 net/core/rtnetlink.c:4538
Code: ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 80 00 00 00 45 8b 76 08 e9 3c ff ff ff e8 40 d7 73 f8 90 <0f> 0b 90 ba 02 00 00 00 48 89 ee 31 ff bb a6 ff ff ff e8 d8 8f f0
RSP: 0018:ffffc90004266df0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000ffffffa6 RCX: ffffffff89968a40
RDX: ffff888034e5a540 RSI: ffffffff89968aa0 RDI: ffff888034e5a540
RBP: ffff88803d24db80 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffa6 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880578ce108
FS:  000055558858a500(0000) GS:ffff8880d5ed8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001140 CR3: 0000000036c7c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 rtmsg_ifinfo_event net/core/rtnetlink.c:4566 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4556 [inline]
 rtnetlink_event+0x137/0x1f0 net/core/rtnetlink.c:7136
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2250
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 netdev_features_change net/core/dev.c:1590 [inline]
 netdev_update_features net/core/dev.c:11108 [inline]
 netdev_update_features net/core/dev.c:11105 [inline]
 netif_disable_lro+0x3e9/0x660 net/core/dev.c:1831
 inetdev_init+0x371/0x570 net/ipv4/devinet.c:284
 inetdev_event+0x7fa/0x17f0 net/ipv4/devinet.c:1590
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2250
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 register_netdevice+0x1998/0x25a0 net/core/dev.c:11484
 macsec_newlink+0x4fb/0x1c50 drivers/net/macsec.c:4221
 rtnl_newlink_create net/core/rtnetlink.c:3913 [inline]
 __rtnl_newlink net/core/rtnetlink.c:4044 [inline]
 rtnl_newlink+0x1499/0x2380 net/core/rtnetlink.c:4159
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2684
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2738
 __sys_sendmsg+0x160/0x210 net/socket.c:2770
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbf0c99e019
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:00007fffe9eca118 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbf0cc25fa0 RCX: 00007fbf0c99e019
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007fbf0ca3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf0cc25fac R14: 00007fbf0cc25fa0 R15: 00007fbf0cc25fa0
 </TASK>

Crashes (150):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/01 13:33 upstream 02dc699f83d0 e611ffe1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/10 06:08 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ba5cc80fd326 5d63f80b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/24 01:01 upstream 62f4c998b297 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/23 08:34 upstream fe2ec83746e5 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/19 02:46 upstream c3d85c669d09 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/18 06:48 upstream 5dd1818b15d9 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/17 19:20 upstream 4982d3552a3b 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/09/17 17:23 upstream 238650ef6c7c 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/17 04:19 upstream 238650ef6c7c 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/15 23:36 upstream 9b87fdc9af2f 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/15 07:33 upstream 587858367581 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/14 21:07 upstream 587858367581 924033e8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in rtmsg_ifinfo_build_skb
2026/09/13 21:23 upstream 2f0c1cf72f46 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/09/13 12:44 upstream 2f0c1cf72f46 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/12 23:49 upstream cba2348ab114 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/11 01:23 upstream 08df884136f1 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/10 23:36 upstream 08df884136f1 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/09/09 17:51 upstream 893e11787f78 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/09/09 04:48 upstream 893e11787f78 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/07 01:29 upstream df2908090cda 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in rtmsg_ifinfo_build_skb
2026/09/05 07:09 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/04 01:07 upstream 841e384b841a 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/09/19 09:10 upstream 40288c9206c1 853b104b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/18 23:35 upstream 5dd1818b15d9 853b104b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/17 01:04 upstream 238650ef6c7c 95928915 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/16 14:40 upstream 9b87fdc9af2f b0e4c57e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/16 10:16 upstream f6e7b42bf05b 12a0a44a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/14 19:11 upstream 704340f1cd0d 924033e8 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/14 02:52 upstream d681d7ef617e 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/13 23:30 upstream d681d7ef617e 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/12 17:21 upstream 5225b8eec4c9 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/12 11:35 upstream 3026c6e4f223 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/12 07:01 upstream 3026c6e4f223 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/12 04:14 upstream 3026c6e4f223 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/07/29 01:09 upstream 3b5f4b83c4ab 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/09/18 00:23 upstream 50d05c7c76c9 8d7d05f1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/17 12:29 upstream 50d05c7c76c9 4a607247 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/14 23:50 upstream 50d05c7c76c9 81a27d1a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/13 11:02 upstream 50d05c7c76c9 70a60e12 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/11 11:42 upstream 50d05c7c76c9 9c29f801 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/08 18:05 upstream 5acbae5f7eb3 351387c4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/09/24 08:47 linux-next 3d7783543c26 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/24 05:45 linux-next 3d7783543c26 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/22 16:51 linux-next a8c591ed6b67 3e2106e5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/22 15:31 linux-next a8c591ed6b67 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/07 15:26 linux-next 9d80aa4617b3 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/09/26 17:02 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8e60d3ddd25 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/25 06:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8e60d3ddd25 f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/25 04:46 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8e60d3ddd25 f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/24 23:25 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8e60d3ddd25 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/24 22:24 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7dc79bb50ab6 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/23 15:09 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/23 04:26 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/21 09:44 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/21 02:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/20 16:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/19 14:05 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/18 11:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/10 18:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/06 16:42 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/09/03 23:09 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci cee9395acd80 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
* Struck through repros no longer work on HEAD.