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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e445621334sm12230366d6.64.2025.02.07.11.41.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Feb 2025 11:41:07 -0800 (PST) Date: Fri, 7 Feb 2025 14:41:05 -0500 From: Gregory Price To: "Bowman, Terry" Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, nifan.cxl@gmail.com, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, dan.j.williams@intel.com, bhelgaas@google.com, mahesh@linux.ibm.com, ira.weiny@intel.com, oohall@gmail.com, Benjamin.Cheatham@amd.com, rrichter@amd.com, nathan.fontenot@amd.com, Smita.KoralahalliChannabasappa@amd.com, lukas@wunner.de, ming.li@zohomail.com, PradeepVineshReddy.Kodamati@amd.com, alucerop@amd.com Subject: Re: [PATCH v5 13/16] cxl/pci: Add error handler for CXL PCIe Port RAS errors Message-ID: References: <20250107143852.3692571-1-terry.bowman@amd.com> <20250107143852.3692571-14-terry.bowman@amd.com> <5df5c06a-b1fe-4b79-a313-2b4c5b088f83@amd.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5df5c06a-b1fe-4b79-a313-2b4c5b088f83@amd.com> On Fri, Feb 07, 2025 at 01:23:06PM -0600, Bowman, Terry wrote: > > > On 2/7/2025 2:01 AM, Gregory Price wrote: > > On Tue, Jan 07, 2025 at 08:38:49AM -0600, Terry Bowman wrote: > >> +static void __iomem *cxl_pci_port_ras(struct pci_dev *pdev) > >> +{ > >> + struct cxl_port *port; > >> + > >> + if (!pdev) > >> + return NULL; > >> + > >> + if ((pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT) || > >> + (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM)) { > >> + struct cxl_dport *dport; > >> + void __iomem *ras_base; > >> + > >> + port = find_cxl_port(&pdev->dev, &dport); > >> + ras_base = dport ? dport->regs.ras : NULL; > > I'm fairly certain dport can come back here uninitialized, you > > probably want to put this inside the `if (port)` block and > > pre-initialize dport to NULL. > Right, it can. NULL dport check here covers this, no?: > > ras_base = dport ? dport->regs.ras : NULL; dport can be garbage (whatever is on the stack) at this check because nothing ever intializes it to NULL. > > Terry > > >> + if (port) > >> + put_device(&port->dev); > >> + return ras_base; > > You can probably even simplify this down to something like > > > > struct_cxl_dport *dport = NULL; > > > > port = find_cxl_port(&pdev->dev, &dport); > > if (port) > > put_device(&port->dev); > > > > return dport ? dport->regs.ras : NULL; > > > > > > ~Gregory >