UBUNTU-CVE-2026-90342: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix mmaplock deadlock on arena lock failure Reported by the Sashiko AI review. arenavmfault() returns VMFAULTRETRY when it can't take arena->spinlock, but it never took mmaplock. The fault path assumes a VMFAULTRETRY handler already dropped mmaplock and re-takes it on the retry, so mmaplock gets taken twice and can deadlock: douseraddrfault() { fault = handlemmfault(...); // calls arenavmfault() if (fault & VMFAULTRETRY) goto retry; // re-locks mmaplock mmapreadunlock(mm); } Return VMFAULTSIGBUS instead, for two reasons: 1. We could keep VMFAULTRETRY, but then we'd have to drop the fault lock first and cap the retry ourselves, the way foliolockorretry() does. 2. A failed rawresspinlockirqsave() already means a possible deadlock was detected, so retrying just hits the same lock again. So returning VMFAULTRETRY here is overkill.