From: bot+bpf-ci@kernel.org
To: dongtai.guo@linux.dev,chenhuacai@kernel.org,yangtiezhu@loongson.cn,hengqi.chen@gmail.com
Cc: kernel@xen0n.name,ast@kernel.org,daniel@iogearbox.net,andrii@kernel.org,martin.lau@linux.dev,eddyz87@gmail.com,memxor@gmail.com,song@kernel.org,yonghong.song@linux.dev,jolsa@kernel.org,shuah@kernel.org,loongarch@lists.linux.dev,linux-kernel@vger.kernel.org,bpf@vger.kernel.org,linux-kselftest@vger.kernel.org,guodongtai@kylinos.cn,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,clm@meta.com,ihor.solodrai@linux.dev
Subject: Re: [PATCH 1/5] LoongArch: BPF: Gate unsupported arena instructions via bpf_jit_supports_insn()
Date: Thu, 18 Jun 2026 04:19:40 +0000 (UTC) [thread overview]
Message-ID: <7e996535cf04f95d2c4e54b1173f4e2d0a96102c737fe030decc432164df97a6@mail.kernel.org> (raw)
In-Reply-To: <20260618033809.98253-2-dongtai.guo@linux.dev>
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> The JIT does not implement atomics on arena pointers (BPF_PROBE_ATOMIC)
> nor sign-extending loads from the arena (BPF_PROBE_MEM32SX). Without a
> bpf_jit_supports_insn() callback the verifier assumes both are available,
> so such programs are accepted only to fail later in the JIT with a
> confusing -EINVAL 'unknown opcode'.
> Implement bpf_jit_supports_insn() to reject these instructions in the
> arena case. The verifier then rejects the program early with a clear
> message ('BPF_ATOMIC stores into R<n> ... is not allowed' / 'sign
> extending loads from arena are not supported yet'). Regular arena
> accesses (BPF_PROBE_MEM32 loads/stores of all sizes) remain supported.
> Signed-off-by: George Guo <guodongtai@kylinos.cn>
This looks like it fixes a gap that was introduced when arena support
was first advertised via bpf_jit_supports_arena() returning true.
Should this carry a Fixes: tag?
Fixes: 4fdb5dd8aeba ("LoongArch: BPF: Implement bpf_addr_space_cast instruction")
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/27735575341
next prev parent reply other threads:[~2026-06-18 4:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-18 3:38 [PATCH 0/5] LoongArch: BPF: arena instruction gating, private stack and exceptions George Guo
2026-06-18 3:38 ` [PATCH 1/5] LoongArch: BPF: Gate unsupported arena instructions via bpf_jit_supports_insn() George Guo
2026-06-18 4:19 ` bot+bpf-ci [this message]
2026-06-18 3:38 ` [PATCH 2/5] LoongArch: BPF: Add private stack support George Guo
2026-06-18 3:38 ` [PATCH 3/5] LoongArch: BPF: Add exceptions (bpf_throw) support George Guo
2026-06-18 3:38 ` [PATCH 4/5] selftests/bpf: Add LoongArch deny list George Guo
2026-06-18 3:38 ` [PATCH 5/5] selftests/bpf: Enable struct_ops private stack test for LoongArch George Guo
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