Re: [PATCH v5] bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-02-17 22:08:33
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On Tue, 17 Feb 2026 10:08:29 -0800 Martin KaFai Lau wrote:
quoted
The reason for the CI test failure.Make sense, but the early point stays the same: the user-provided skb can have unexpected data. Either an skb->protocol is not handled here, or the earlier dst lookup has an error. I don't know what the current active users left in lwt are. Unless there is an issue with missing skb_dst() in other mainstream program types (e.g., tc), I would prefer to add a check in bpf_lwt_push_ip_encap() instead of complicating bpf_prog_test_run_skb() further.
Can bpf_prog_test_run_skb() simply not support LWT then? Having fastpath checks for test harness really feels like duct tape