UBUNTU-CVE-2026-98796: Low severity ubuntu/linux-azure vulnerability

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mtkethsoc: allocate dummy netdev sooner The RX rings and the shared NAPI are carried by an internal "dummy" netdev (eth->dummydev). mtkprobe() creates that dummy device, and adds the shared tx/rx NAPI to it, only after the MAC netdevs have been registered. That order has been there since the MT7623 support was added and leaves a window in which the netdevs are visible to the network core before the shared NAPI and the dummy device exist. If anything brings the first netdev up during that window (e.g. netifd opening the WAN link the instant the interface is registered), the first-open path runs without them. On NETSYS v2 and later SoCs mtkrxalloc() -> xdprxqinforeg() then dereferences eth->dummydev == NULL: WARNING: CPU: ... Missing netdevice from driver in net/core/xdp.c and mtkopen() fails with -ENODEV. On NETSYS v1 SoCs (MT7621/MT7622/MT7623/MT7629) there is no page pool, so the same open instead calls napienable() on a napistruct that netifnapiadd() has not initialised yet and dereferences a NULL napi->dev. Allocate the dummy netdev and add the shared tx/rx NAPI to it before the registernetdev() loop. Both the dummy-allocation failure and a registernetdev() failure now unwind through mtkunregdev(), which unregisters the netdevice notifiers and the netdevs registered so far, stopping a concurrently-opened netdev (ndostop) and its NAPI before the dummy carrier is freed. A netdev that opened during the window can also have queued the frame-engine reset worker (via the tx watchdog or phylink), so the probe error path now cancels eth->pendingwork before freeing the shared state, as mtkcleanup() already does on remove.