From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-244108.protonmail.ch (mail-244108.protonmail.ch [109.224.244.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9454F35E92F; Fri, 28 Aug 2026 19:12:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=109.224.244.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787944346; cv=none; b=A6w27s0UR+nhqpdqPAGb0T4eUPU+UEEjoseljJYn+4GzesKsflU5bY2l6B7KwLvsnWxMomem1X1/aX3KmibOXNb48gmCzCDx9SpistMUGVEov5bJpnYwSWv8PXOP1rZ/dDk2r3xhb4ZrAEfCfylnF15FzFw5CxQKTyQnn3LZsGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787944346; c=relaxed/simple; bh=w4nQpbW2SJfEH8/UMUa+zqT9BEUAGKdaa63d0JTf3Eg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dWILURSDEwyieALPWD4gPIfcUfYfTTVD3yMdWwH6szDblI302teW6Dxu+1ItvA8Z9ypticIqjfV5NVs/M+e3HL5QFpM4d5DMrNsUy6Qdx9lmpoDuVcSj4M43n8Cv+EFwVmN7A7L9ujF8XhxexLMtObDHY9acyl9f7lmAwz9mSNA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=onurozkan.dev; spf=pass smtp.mailfrom=onurozkan.dev; dkim=pass (2048-bit key) header.d=onurozkan.dev header.i=@onurozkan.dev header.b=MCku4eFE; arc=none smtp.client-ip=109.224.244.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=onurozkan.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=onurozkan.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=onurozkan.dev header.i=@onurozkan.dev header.b="MCku4eFE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=onurozkan.dev; s=protonmail; t=1787944337; x=1788203537; bh=FeJlaW2B8oO576wp67QQ5FK5OyHGETUHK344nwqMpYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:From:To: Cc:Date:Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=MCku4eFEFfnuU4wTKnRsvfHFKD9y0nP4mJ8meIJAAV5WwadywMYJu18hVP3D1GIcQ RLj7CcybbRpYMPgQwQ90aBxYne1p96UAy0EGD/qe+W8fKQ2CBKhgh/sjhCAE0rOKx6 rV30iq5XHWCpJcP2s/rcYdXiY97CPtv01IofiOz+As89ttOIi/iIMoSbV3kLvFLSDH 17JtkybS0JuGH/ivSEtkhjrpMIhxYwR3oQf+TuL1XRbFD8BKZPkPmNKzK0bJyjy7Oa rSMBBNsVZsph4CTYNj7wOGW8YiSUkt6xdNAeWZ9/F28zDykCZQtYFvelR1R1B/yxTY 7uF4RquQFcfvg== X-Pm-Submission-Id: 4hWp0t3wnKz2Scht From: =?UTF-8?q?Onur=20=C3=96zkan?= To: Mehmet Koseoglu Cc: rafael@kernel.org, viresh.kumar@linaro.org, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, dakr@kernel.org, daniel.almeida@collabora.com, tamird@kernel.org, acourbot@nvidia.com, linux-pm@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] rust: cpufreq: reject NULL from cpufreq_cpu_get() Date: Fri, 28 Aug 2026 22:11:45 +0300 Message-ID: <20260828191213.45530-1-work@onurozkan.dev> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260828161834.29539-1-mehmet.mkoseoglu@gmail.com> References: <20260828161834.29539-1-mehmet.mkoseoglu@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, 28 Aug 2026 19:16:57 +0300=0D Mehmet Koseoglu wrote:=0D =0D Hi Mehmet,=0D =0D > cpufreq_cpu_get() returns either a referenced policy or NULL.=0D > PolicyCpu::from_cpu() passed its return value to from_err_ptr(), which=0D > rejects ERR_PTR values but accepts NULL.=0D > =0D > If the lookup fails, Policy::from_raw_mut() therefore constructs a mutabl= e=0D > reference from NULL. Dropping the resulting PolicyCpu then passes the=0D > invalid pointer to cpufreq_cpu_put(), causing an oops in kobject_put().=0D > =0D > Reject NULL with NonNull before constructing the Policy reference. Return= =0D > ENODEV instead.=0D > =0D > A KUnit negative-control run reproduced the oops with the original=0D > conversion. The same test passed with this change. The reproducer is=0D > available on request.=0D > =0D > Fixes: 6ebdd7c93177 ("rust: cpufreq: Extend abstractions for policy and d= river ops")=0D > Assisted-by: LLM=0D > Signed-off-by: Mehmet Koseoglu =0D =0D This should be tagged for stable:=0D =0D Cc: stable@vger.kernel.org=0D =0D LGTM otherwise.=0D =0D > ---=0D > Changes in v2:=0D > - Format modified imports using the kernel's vertical import style.=0D > =0D > rust/kernel/cpufreq.rs | 18 ++++++++++++++----=0D > 1 file changed, 14 insertions(+), 4 deletions(-)=0D > =0D > diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs=0D > index affa2b9490ef..4b992ea9a0f0 100644=0D > --- a/rust/kernel/cpufreq.rs=0D > +++ b/rust/kernel/cpufreq.rs=0D > @@ -14,7 +14,13 @@=0D > cpumask,=0D > device::{Bound, Device},=0D > devres,=0D > - error::{code::*, from_err_ptr, from_result, to_result, Result, VTABL= E_DEFAULT_ERROR},=0D > + error::{=0D > + code::*,=0D > + from_result,=0D > + to_result,=0D > + Result,=0D > + VTABLE_DEFAULT_ERROR, //=0D > + },=0D > ffi::{c_char, c_ulong},=0D > prelude::*,=0D > types::ForeignOwnable,=0D > @@ -29,7 +35,10 @@=0D > marker::PhantomData,=0D > ops::{Deref, DerefMut},=0D > pin::Pin,=0D > - ptr,=0D > + ptr::{=0D > + self,=0D > + NonNull, //=0D > + },=0D > };=0D > =0D > use macros::vtable;=0D > @@ -687,12 +696,13 @@ fn clear_data(&mut self) -> Opti= on {=0D > impl<'a> PolicyCpu<'a> {=0D > fn from_cpu(cpu: CpuId) -> Result {=0D > // SAFETY: It is safe to call `cpufreq_cpu_get` for any valid CP= U.=0D > - let ptr =3D from_err_ptr(unsafe { bindings::cpufreq_cpu_get(u32:= :from(cpu)) })?;=0D > + let ptr =3D=0D > + NonNull::new(unsafe { bindings::cpufreq_cpu_get(u32::from(cp= u)) }).ok_or(ENODEV)?;=0D > =0D > Ok(Self(=0D > // SAFETY: The `ptr` is guaranteed to be valid and remains v= alid for the lifetime of=0D > // the returned reference.=0D > - unsafe { Policy::from_raw_mut(ptr) },=0D > + unsafe { Policy::from_raw_mut(ptr.as_ptr()) },=0D > ))=0D > }=0D > }=0D > -- =0D > 2.55.0=0D