CVE-2026-98050 — mlxsw: spectrum_ptp: Fix napi_gro_receive() call from GC workqueue context

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

mlxsw: spectrum_ptp: Fix napi_gro_receive() call from GC workqueue context

Currently mlxsw_sp1_ptp_ht_gc_collect() is run from the PTP garbage-collection workqueue, rather than the NAPI poll context. For any unmatched PTP entries carrying an SKB, it calls mlxsw_sp1_ptp_unmatched_finish() -> mlxsw_sp1_ptp_packet_finish(). For ingress packets, this calls mlxsw_sp_rx_listener_no_mark_func(). The end of that function is the following:

skb->protocol = eth_type_trans(skb, skb->dev); napi_gro_receive(mlxsw_skb_cb(skb)->rx_md_info.napi, skb);

The napi pointer is one that was placed in the SKB control block when the trapped packet was received in the NAPI context. Later, when the GC reaps the unmatched entry (up to MLXSW_SP1_PTP_HT_GC_TIMEOUT later), the call to napi_gro_receive() mutates the NAPI instance's GRO list, which is unsafe if the poll is running concurrently on another CPU.

In mlxsw_sp1_ptp_ht_gc_collect(), local_bh_disable() is called to prevent softirq processing, but this only applies to the local CPU. Additionally, its comment is stale. It states that mlxsw_sp1_ptp_unmatched_finish() invokes netif_receive_skb(). This has not been accurate since the referenced commit; this patch makes that comment accurate again. mlxsw_pci_napi_devs_init() calls netif_threaded_enable() on the NAPI RX net_device without any conditions. The NAPI instance's poll, which may be running concurrent to the GC, is r…

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CVE-2026-98050 — mlxsw: spectrum_ptp: Fix napi_gro_receive() call from GC workqueue context