From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5D265360EC2 for ; Mon, 1 Jun 2026 19:06:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780340784; cv=none; b=sDCfxdg1j8bk9/dBRJ5btOsBNUCt9KITs4Cw5UyQz7grI8WyinWRKdvLvu9B0LppWWcSuAVXwYRD4jb16RRAG36Lef9qw7HaRDxT4Eg+wNnqmQrMlKzXTl6YZmjF5u9e2kjqccKAYCwV1IWcqqiBDOgRQuTRTVXr1nq2vD3dEDA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780340784; c=relaxed/simple; bh=XQjMisD5+yAPpVk3seej5PqD1GHJUHe/24awhYC/1no=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=F0sxbBO2brmpTuNT2PizImTG108VT0XE5Kfg/hGxabSWaxEbfAkWJ5hGizsU1QRcEDls83le0ojtxTiWHJCibnT65Ma8yvLM2JQGrLmRfGHXdq3v57fDqjSQ6/iqQOlUafjdLBEzojGvBC8SpAg1KET6d0XRhGnkV99eMt3u4C4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e3rd4Cjx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="e3rd4Cjx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 269F81F00893; Mon, 1 Jun 2026 19:06:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780340783; bh=8KL8l8BHCkygJfW4p1KD0V1xnlQb8EJAruObPiOl6vQ=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=e3rd4CjxkPAsTfWJfaMoVERk2im4yaDjKgj5xgsEMfckC7HCwa85Qfije5YnXjPMq lysGVLQb98JoOrdBwg3X/E6jh6S9DrD2oUWPSmRYFyMfjrOrP1TrIUaftrWPDZNeFs YzbEpefrvcxbxU6GEwWnjXLEl6O22pG/0cJVmdYt239Vn2C6bfzsIDMwG0ZWXNUD5M Jov+psk+NTG8ZNGywBSOwak4sFOaxl7CKuQWohQ7xoUS4OKAym27CuQejktFvBUDRL LDJpJa7bYhZ7dwHZvB5lkATu7QCUUWldBt6ahE3JHZEqDJd3OXunm5urIt8hDFgGOM oBKnIT9t1xDSQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH 6/6] PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats() Reply-To: sashiko-reviews@lists.linux.dev To: "Pranjal Shrivastava" Cc: linux-pci@vger.kernel.org In-Reply-To: <20260601134204.2150602-7-praan@google.com> References: <20260601134204.2150602-7-praan@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 01 Jun 2026 19:06:22 +0000 Message-Id: <20260601190623.269F81F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] Adding a WARN_ON() to pci_prepare_ats() causes spurious kernel war= nings and potential panics because the ARM SMMUv3 driver does not check pci= _ats_supported() prior to calling it. -- commit eaccac64f7c8e00ef695d5c2076021c097520251 Author: Pranjal Shrivastava PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats() This commit updates pci_prepare_ats() to wrap the internal pci_ats_supported() check in a WARN_ON(). It is intended to mandate that all callers verify ATS support before calling the function. > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > --- a/drivers/pci/ats.c > +++ b/drivers/pci/ats.c > @@ -61,7 +63,7 @@ int pci_prepare_ats(struct pci_dev *dev, int ps) > { > u16 ctrl; > =20 > - if (!pci_ats_supported(dev)) > + if (WARN_ON(!pci_ats_supported(dev))) [Severity: High] Will this trigger spurious warnings or panics for non-ATS PCI devices on ARM systems? The arm_smmu_probe_device() function appears to unconditionally invoke pci_prepare_ats() for all PCI devices without verifying ATS support first: drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:arm_smmu_probe_device() { ... if (dev_is_pci(dev)) { unsigned int stu =3D __ffs(smmu->pgsize_bitmap); pci_prepare_ats(to_pci_dev(dev), stu); } ... } Since this unpatched caller does not check pci_ats_supported() first, any standard PCI device lacking ATS support might trigger this new WARN_ON() during IOMMU device probe. > return -EINVAL; --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260601134204.2150= 602-1-praan@google.com?part=3D6