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[128.178.122.107]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a00cf9b150sm3372535e9.7.2026.09.28.09.22.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2026 09:22:20 -0700 (PDT) From: spidermana To: mehmet.mkoseoglu@gmail.com Cc: a.hindborg@kernel.org, acourbot@nvidia.com, aliceryhl@google.com, bjorn3_gh@protonmail.com, boqun@kernel.org, dakr@kernel.org, daniel.almeida@collabora.com, gary@garyguo.net, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, lossin@kernel.org, ojeda@kernel.org, rafael@kernel.org, rust-for-linux@vger.kernel.org, tamird@kernel.org, tmgross@umich.edu, viresh.kumar@linaro.org, work@onurozkan.dev Subject: Re: [PATCH v3] rust: cpufreq: reject NULL from cpufreq_cpu_get() Date: Mon, 28 Sep 2026 18:22:14 +0200 Message-ID: <20260928162214.487564-1-xuyiwen14@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260829161013.102967-1-mehmet.mkoseoglu@gmail.com> References: <20260829161013.102967-1-mehmet.mkoseoglu@gmail.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Sat, 29 Aug 2026 19:10:13 +0300, Mehmet Koseoglu wrote: > cpufreq_cpu_get() returns either a referenced policy or NULL. > PolicyCpu::from_cpu() passed its return value to from_err_ptr(), which > rejects ERR_PTR values but accepts NULL. [...] > Ok(Self( > // SAFETY: The `ptr` is guaranteed to be valid and remains valid for the lifetime of > // the returned reference. > - unsafe { Policy::from_raw_mut(ptr) }, > + unsafe { Policy::from_raw_mut(ptr.as_ptr()) }, Just a quick nit here, maybe rephrase this SAFETY comment, e.g.: // SAFETY: `ptr` is non-NULL and `cpufreq_cpu_get()` took a reference on it, so it is // valid for writing and remains valid for the lifetime of the returned reference. Either way, looks good to me. FWIW, I hit this too and have a reproducer [1]. [1] https://github.com/Rust-for-Linux/linux/issues/1258 Reviewed-by: Elowen Xu