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
First crash: 17d, last: 11h22m
✨ 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 (2)
Title Replies (including bot) Last reply
Re: [syzbot] [net?] WARNING in rtmsg_ifinfo_build_skb 2 (3) 2026/08/14 23:14
[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 (36):
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
2026/08/12 13:54 upstream f5bbbfec59b4 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/08/12 10:09 upstream f5bbbfec59b4 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in rtmsg_ifinfo_build_skb
2026/08/07 07:30 upstream 364465ab19de c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/05 07:15 upstream c21bb4193868 b3eac40e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/03 09:16 upstream 075b74841bd0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/08/01 21:21 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/01 21:21 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/01 05:44 upstream 0131b508c0e2 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/01 05:44 upstream 0131b508c0e2 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in rtmsg_ifinfo_build_skb
2026/08/14 12:25 upstream 2f1baf1fc892 2cf1fbb7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/09 23:08 upstream b643e495ae92 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/09 08:08 upstream 06cf61899d64 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/08 14:59 upstream a59f57e2aa12 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/07 13:39 upstream f9a2394a2348 e4ef95d6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/07 04:35 upstream fcaeecb8b0cd c38879ea .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/05 16:27 upstream c21bb4193868 1eed00d1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/04 11:20 upstream 848acc8ffe1b 3c5eaa21 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/01 19:02 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/01 13:39 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in rtmsg_ifinfo_build_skb
2026/08/01 12:29 upstream 02dc699f83d0 e611ffe1 .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
2026/08/14 15:01 upstream 2f1baf1fc892 2cf1fbb7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/12 21:26 upstream 3d6d817622b0 359b2492 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/09 10:10 upstream 06cf61899d64 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/09 06:01 upstream 06cf61899d64 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/07 11:30 upstream f9a2394a2348 e4ef95d6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/02 19:27 upstream bd1dde877520 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/07/31 22:06 upstream a2cf4ef33184 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in rtmsg_ifinfo_build_skb
2026/08/14 03:05 linux-next 2697ef8943c9 b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/08/08 11:45 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/08/08 11:45 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/08/08 11:44 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in rtmsg_ifinfo_build_skb
2026/08/06 12:37 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in rtmsg_ifinfo_build_skb
2026/08/03 22:06 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 a68cb31b .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.