From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-43171.protonmail.ch (mail-43171.protonmail.ch [185.70.43.171]) (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 0D2DA353A7F; Sat, 29 Aug 2026 19:53:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.43.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788033191; cv=none; b=PCkjy7Rm7cCP5mhNz3mYZFPBJOVEkGUVBrGglPrRE+/Ie5aH2X3NEJS0MznhaUdzgpmbkCqljlNmrM34Ns4w0joG2D5V37QOJpaJFbAtgkevhlQd7vdEZ5YLUFKJajwzH2wMvM1QgmHA+eg4XnNukiuwzRg0lMVYlqrVEqFTqE4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788033191; c=relaxed/simple; bh=UrzGbiUpmLrHNiKTBB99Yi6K10TIVUQB17wqWsBIXaA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=YviY51hXHhqmUBDBdL0+LlSziQ4WSaRFfr6KDtwL7rsLcSGk43KWLV51Q5bUw0RWISVuSOjI1O6Xzns2TrjbkhcX4W97LfAI8c/aWcyxmQweDkd9peq6PcYUr5b8c6qZPvXNP7kTqo8Ok2MOvzqBLDKjfl6ONgmQT+nZ1j7FMbo= 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=Ji0kb+hz; arc=none smtp.client-ip=185.70.43.171 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="Ji0kb+hz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=onurozkan.dev; s=protonmail; t=1788033176; x=1788292376; bh=/dEiKOIuv+SZQFcpv7PhRYypxPlBSUlnYBm5pdQOQRY=; 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=Ji0kb+hzhZttPBszUxW85mbpMZST7a8OFyDAne2OXLUNDN4uB4hI8Me5kFUKmuDz6 BvPX21StRW6wcqSjcPxvpD/kF52A7bLU9gy64VytZM5UWxSsCVFKcVis+DGXkiDXM3 UwztLIUkdegaJI5hE4zArsDwIttVzbIXMvyI7JG9iE8jG5QIil96HhYj3zWdFb2dR4 vfrshmHDCWVElUjT48DyTdUxGzQqSMb9bpOBiFa5xFKW7vfiy1lRQMrB8+B6xY8fxB /WSDk+4r4wPKWuya3Be/+BIOhhIdV1U6KfOTx5clPpPuTCM0WMPpcnRGFAKgVtzGpG rXMkXhpV+pfOw== X-Pm-Submission-Id: 4hXQsH4xqyz1DFFg 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, =?UTF-8?q?Onur=20=C3=96zkan?= Subject: Re: [PATCH v3] rust: cpufreq: reject NULL from cpufreq_cpu_get() Date: Sat, 29 Aug 2026 22:52:45 +0300 Message-ID: <20260829195250.24625-1-work@onurozkan.dev> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260829161013.102967-1-mehmet.mkoseoglu@gmail.com> References: <20260829161013.102967-1-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 Sat, 29 Aug 2026 19:10:13 +0300=0D Mehmet Koseoglu wrote:=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 > Cc: stable@vger.kernel.org=0D > Assisted-by: LLM=0D > Signed-off-by: Mehmet Koseoglu =0D =0D Reviewed-by: Onur =C3=96zkan =0D =0D > ---=0D > Changes in v3:=0D > - Add Cc: stable@vger.kernel.org.=0D > =0D > Changes in v2:=0D > - Format modified imports using the kernel's vertical import style.=0D > =0D > v2: https://lore.kernel.org/r/20260828161834.29539-1-mehmet.mkoseoglu@gma= il.com=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