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: 335d, last: 26d
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 (12)
Created Duration User Patch Repo Result
2026/03/21 21:16 23m retest repro net-next OK log
2026/03/21 21:16 36m retest repro net-next OK log
2026/03/21 21:16 24m retest repro net-next OK log
2026/03/21 13:59 36m retest repro net OK log
2026/03/21 13:59 23m retest repro net OK log
2026/03/21 08:16 27m retest repro net-next OK log
2026/03/21 08:16 1h24m retest repro net-next OK log
2026/03/21 08:16 2h27m retest repro net-next OK log
2026/03/21 08:16 1h07m retest repro upstream OK log
2026/03/21 08:16 23m retest repro net-next OK log
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: NLM_F_CREATE should be set when creating new route
IPv6: NLM_F_CREATE should be set when creating new route
------------[ cut here ]------------
i != fen6_info->nsiblings
WARNING: drivers/net/netdevsim/fib.c:831 at nsim_fib6_event_init drivers/net/netdevsim/fib.c:831 [inline], CPU#2: syz.0.17/6063
WARNING: drivers/net/netdevsim/fib.c:831 at nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline], CPU#2: syz.0.17/6063
WARNING: drivers/net/netdevsim/fib.c:831 at nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline], CPU#2: syz.0.17/6063
WARNING: drivers/net/netdevsim/fib.c:831 at nsim_fib_event_nb+0xbc1/0xe40 drivers/net/netdevsim/fib.c:1043, CPU#2: syz.0.17/6063
Modules linked in:
CPU: 2 UID: 0 PID: 6063 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: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+0xbc1/0xe40 drivers/net/netdevsim/fib.c:1043
Code: 20 48 8b 6c 24 28 e8 9e 39 cd fa e8 99 39 cd fa 44 89 fe 44 89 ef e8 7e 33 cd fa 45 39 fd 0f 84 6a fd ff ff e8 80 39 cd fa 90 <0f> 0b 90 e9 5c fd ff ff e8 72 39 cd fa 48 c7 c7 20 16 7d 8c e8 26
RSP: 0018:ffffc900030f7118 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffc900030f7260 RCX: ffffffff873b6272
RDX: ffff88802a638000 RSI: ffffffff873b6280 RDI: ffff88802a638000
RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888038a08000
R13: 0000000000000002 R14: ffff8880296d4f00 R15: 0000000000000001
FS:  000055557d45e500(0000) GS:ffff8880d6548000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 000000004075e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 notifier_call_chain+0x99/0x420 kernel/notifier.c:85
 atomic_notifier_call_chain+0x71/0x1c0 kernel/notifier.c:223
 call_fib_notifiers+0x33/0x70 net/core/fib_notifier.c:35
 call_fib6_multipath_entry_notifiers+0x112/0x170 net/ipv6/ip6_fib.c:425
 ip6_route_multipath_add+0x128f/0x1ba0 net/ipv6/route.c:5535
 inet6_rtm_newroute+0xf5/0x160 net/ipv6/route.c:5657
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa54/0xc30 net/socket.c:2592
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646
 __sys_sendmsg+0x170/0x220 net/socket.c:2678
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f15beb9c629
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:00007ffe852e2628 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f15bee15fa0 RCX: 00007f15beb9c629
RDX: 0000000000000000 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007f15bec32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f15bee15fac R14: 00007f15bee15fa0 R15: 00007f15bee15fa0
 </TASK>

Crashes (904):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/20 16:40 upstream 8bf22c33e7a1 741f5161 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream 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
2026/02/28 13:19 upstream 4d349ee5c778 43249bac .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-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
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
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
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
2026/03/03 00:07 upstream 11439c4635ed b9dd6534 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/03/01 12:13 upstream eb71ab2bf722 43249bac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/03/01 03:49 upstream 2f9339c052bd 43249bac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/03/01 01:14 upstream 2f9339c052bd 43249bac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/25 17:53 upstream 7dff99b35460 c162cde9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/25 03:03 upstream 7dff99b35460 787dfb7c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/02/24 12:16 upstream 7dff99b35460 96b1aa46 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/24 05:33 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/21 20:04 upstream d79526b89571 6e7b5511 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/21 06:29 upstream a95f71ad3e2e 6e7b5511 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nsim_fib_event_nb
2026/02/20 01:04 upstream 2b7a25df823d 73a252ac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/19 23:53 upstream 2b7a25df823d 73a252ac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/19 20:54 upstream 2b7a25df823d 73a252ac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/19 16:58 upstream 2b7a25df823d 73a252ac .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/18 01:47 upstream d295082ea672 4db8fa92 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/15 17:05 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/15 14:03 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/15 11:10 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in nsim_fib_event_nb
2026/02/12 19:30 upstream 37a93dd5c49b 504cb1bf .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream 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
2026/01/26 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
2026/02/20 17:00 net bfd264fbbbca 741f5161 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce 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
2026/01/08 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
2026/03/06 03:48 net-next ab99e1167293 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/03/03 23:40 net-next ed0abfe93fd1 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/02/20 19:31 net-next 8bf22c33e7a1 741f5161 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in nsim_fib_event_nb
2026/02/17 16:25 net-next 37a93dd5c49b e439b951 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-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
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
2026/01/27 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
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.