BUG: Address fc00:: on device lo is missing its host route.

Status: upstream: reported on 2026/08/07 12:56
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+ded267b328e950a7c0c4@syzkaller.appspotmail.com
First crash: 5d12h, last: 1d18h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
2bf80966 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ BUG: Address fc00:: on device lo is missing its host route. 2026/08/09 09:44 2026/08/09 09:44 2026/08/09 10:57 5d63f80b
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] ipv6: addrconf: drop "BUG: " prefix from pr_warn() 2 (2) 2026/08/10 09:51
[syzbot] BUG: Address fc00:: on device lo is missing its host route. 0 (1) 2026/08/07 12:56
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 BUG: Address fc00:: on device lo is missing its host route. -1 1 4d14h 4d14h 0/2 premoderation: reported on 2026/08/05 17:27
android-6-12 BUG: Address fc00:: on device lo is missing its host route. -1 1 4d00h 4d00h 0/1 premoderation: reported on 2026/08/06 07:35
linux-6.1 BUG: Address fc00:: on device lo is missing its host route. -1 2 2d09h 2d09h 0/3 upstream: reported on 2026/08/07 23:09

Sample crash report:
IPv6: BUG: Address fc00:: on device lo is missing its host route.
bond9: (slave ip6gretap1): link status up, enabling it in 0 ms
bond9: (slave ip6gretap1): failed to get link speed/duplex
bond9: (slave ip6gretap1): link status up, enabling it in 0 ms
bond9: (slave ip6gretap1): failed to get link speed/duplex
bond9: (slave ip6gretap1): link status up, enabling it in 0 ms
bond9: (slave ip6gretap1): failed to get link speed/duplex
net_ratelimit: 80 callbacks suppressed
bond9: (slave ip6gretap1): link status up, enabling it in 0 ms
bond9: (slave ip6gretap1): failed to get link speed/duplex
bond9: (slave ip6gretap1): link status up, enabling it in 0 ms
bond9: (slave ip6gretap1): failed to get link speed/duplex

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 11:41 upstream 364465ab19de e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/07 11:38 upstream 364465ab19de e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/06 01:44 upstream 0d8395707651 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/08 02:58 upstream 3f008280327b 5d63f80b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/08 02:58 upstream 3f008280327b 5d63f80b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/08 02:58 upstream 3f008280327b 5d63f80b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: Address fc00:: on device lo is missing its host route.
2026/08/07 08:50 upstream fcaeecb8b0cd c38879ea .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: Address fc00:: on device lo is missing its host route.
2026/08/07 08:49 upstream fcaeecb8b0cd c38879ea .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: Address fc00:: on device lo is missing its host route.
2026/08/08 13:32 linux-next cc2b5f627e8c 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce BUG: Address fc00:: on device lo is missing its host route.
2026/08/06 16:06 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: Address fc00:: on device lo is missing its host route.
2026/08/04 20:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: Address fc00:: on device lo is missing its host route.
* Struck through repros no longer work on HEAD.