syzbot


WARNING in nsim_fib_event_nb

Status: upstream: reported C repro on 2025/05/01 15:06
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+a259a17220263c2d73fc@syzkaller.appspotmail.com
First crash: 284d, last: 19h41m
Cause bisection: introduced by (bisect log) :
commit e6f497955fb6a072999db491a01dd3a203d5bcea
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Fri Apr 18 00:03:45 2025 +0000

  ipv6: Check GATEWAY in rtm_to_fib6_multipath_config().

Crash: WARNING in nsim_fib_event_nb (log)
Repro: C syz .config
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH 1/1] ipv6: Check AF_UNSPEC in ip6_route_multipath_add() 8 (8) 2025/09/30 14:13
[syzbot] [net?] WARNING in nsim_fib_event_nb 1 (4) 2025/09/07 21:48
Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/09/07 21:48 28m maksimilijan.marosevic@proton.me https://github.com/mm51593/linux 2871306d95759d0e38f9ce636e1bef6aef431aa8 OK log
2025/05/30 16:42 43m charmitro@posteo.net https://github.com/charmitro/linux.git a5ecfdd98680b51a58a570660086f871873506f4 report log

Sample crash report:
IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE
IPv6: NLM_F_CREATE should be set when creating new route
IPv6: NLM_F_CREATE should be set when creating new route
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5861 at drivers/net/netdevsim/fib.c:831 nsim_fib6_event_init drivers/net/netdevsim/fib.c:831 [inline]
WARNING: CPU: 1 PID: 5861 at drivers/net/netdevsim/fib.c:831 nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline]
WARNING: CPU: 1 PID: 5861 at drivers/net/netdevsim/fib.c:831 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline]
WARNING: CPU: 1 PID: 5861 at drivers/net/netdevsim/fib.c:831 nsim_fib_event_nb+0xed8/0x1080 drivers/net/netdevsim/fib.c:1043
Modules linked in:
CPU: 1 UID: 0 PID: 5861 Comm: syz-executor316 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:nsim_fib6_event_init drivers/net/netdevsim/fib.c:831 [inline]
RIP: 0010:nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline]
RIP: 0010:nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline]
RIP: 0010:nsim_fib_event_nb+0xed8/0x1080 drivers/net/netdevsim/fib.c:1043
Code: fa be 02 00 00 00 eb 0a e8 95 97 bb fa be 01 00 00 00 4c 89 f7 e8 08 c2 b4 fd 4c 8b 64 24 08 e9 91 f4 ff ff e8 79 97 bb fa 90 <0f> 0b 90 e9 70 fb ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 35
RSP: 0018:ffffc90003f7f068 EFLAGS: 00010293
RAX: ffffffff87048e47 RBX: 0000000000000002 RCX: ffff8880339dbc00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffff888146badc2f R09: 1ffff11028d75b85
R10: dffffc0000000000 R11: ffffed1028d75b86 R12: ffff888032f28000
R13: ffffc90003f7f1e0 R14: 0000000000000001 R15: ffffc90003f7f1f8
FS:  000055556c80a380(0000) GS:ffff888125d57000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000077970000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223
 call_fib_notifiers+0x31/0x60 net/core/fib_notifier.c:35
 call_fib6_multipath_entry_notifiers+0xe6/0x150 net/ipv6/ip6_fib.c:425
 ip6_route_multipath_add net/ipv6/route.c:5525 [inline]
 inet6_rtm_newroute+0x12f5/0x18c0 net/ipv6/route.c:5647
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 ____sys_sendmsg+0x505/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f748dd03fe9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe9910b088 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f748dd03fe9
RDX: 0000000000000000 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Crashes (866):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/09 15:12 upstream 038d61fd6422 32a0e5ed .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in nsim_fib_event_nb
2025/12/26 15:45 upstream ccd1cdca5cd4 d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/08 04:40 net 653267321f05 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 09:57 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 08:24 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 06:47 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 05:19 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 03:55 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/05/01 02:26 net-next deeed351e982 ce7952f4 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 08:03 upstream 62085877ae65 4f25b9b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in nsim_fib_event_nb
2026/01/22 20:34 upstream a66191c590b3 2367ed1e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in nsim_fib_event_nb
2026/01/06 19:34 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in nsim_fib_event_nb
2026/01/06 11:59 upstream 7f98ab9da046 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in nsim_fib_event_nb
2026/01/05 19:28 upstream 3609fa95fb0f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nsim_fib_event_nb
2026/01/04 16:51 upstream aacb0a6d604a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in nsim_fib_event_nb
2025/12/31 09:35 upstream dbf8fe85a16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in nsim_fib_event_nb
2025/10/18 05:47 upstream f406055cb18c 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in nsim_fib_event_nb
2026/01/19 18:26 upstream 24d479d26b25 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in nsim_fib_event_nb
2026/01/07 15:35 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in nsim_fib_event_nb
2026/02/09 03:45 upstream e98f34af6116 4c131dc4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/06 01:20 upstream 8fdb05de0e2d f03c4191 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/05 16:44 upstream f14faaf3a1fb 4936e85c .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/04 20:03 upstream 5fd0a1df5d05 ea10c935 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/01 15:57 upstream 162b42445b58 6b8752f2 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/31 22:11 upstream ad9a728a3388 afc0c4d4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/25 18:13 upstream d91a46d6805a 40acda8a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/25 16:12 upstream d91a46d6805a 40acda8a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/23 20:11 upstream c072629f05d7 1aa92270 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/23 20:09 upstream c072629f05d7 1aa92270 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/22 07:47 upstream cf38b2340c0e d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/19 12:40 upstream 24d479d26b25 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/19 07:42 upstream 24d479d26b25 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/15 20:22 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/14 17:11 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/09 09:55 upstream 623fb9912f6a d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/08 07:36 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/07 12:49 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/01/07 11:24 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2025/12/31 02:55 upstream dbf8fe85a16a d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/01/26 15:12 upstream 63804fed149a 55756628 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in nsim_fib_event_nb
2025/10/22 07:24 upstream 211ddde0823f 252fbbad .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in nsim_fib_event_nb
2025/09/23 13:28 upstream cec1e6e5d1ab 0ac7291c .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in nsim_fib_event_nb
2025/09/13 17:20 upstream 22f20375f5b7 e2beed91 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING in nsim_fib_event_nb
2025/07/24 10:22 upstream f9af7b5d9349 0c1d6ded .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in nsim_fib_event_nb
2026/01/31 18:39 net 6d06bc83a5ae 35764559 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/28 15:33 net a040afa3bca4 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 21:21 net 8016dc5ee19a 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 14:44 net 8016dc5ee19a 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 11:51 net 8016dc5ee19a 4f25b9b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/23 02:11 net 4a3dba481882 82c9c083 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/20 10:04 net 58bae918d73e 572effc1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/20 00:58 net 2c28769a51de d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/18 02:37 net a80c9d945aef d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/15 22:55 net 4156c3745f06 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/14 07:25 net ffe4ccd359d0 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/12 17:18 net 16ce6e6fa946 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/12 02:54 net 16ce6e6fa946 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/10 08:25 net 7470a7a63dc1 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in nsim_fib_event_nb
2026/01/27 21:19 net-next 099ca4121ea7 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 20:04 net-next eac026ff97a9 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/24 18:32 net-next eac026ff97a9 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/20 13:31 net-next c5e7b1d1cc8a 572effc1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/20 03:03 net-next d321d505edb6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/16 10:35 net-next d4596891e72c d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/11 09:48 net-next 959728f9931e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/12/28 08:12 net-next 7b8e9264f55a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2025/12/26 13:28 net-next 7b8e9264f55a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/01/27 13:05 linux-next 615aad0f61e0 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsim_fib_event_nb
2026/01/18 16:49 linux-next 46fe65a2c28e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsim_fib_event_nb
2025/11/10 15:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e424ed997df8 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in nsim_fib_event_nb
* Struck through repros no longer work on HEAD.