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[149.200.78.10]) by smtp.gmail.com with ESMTPSA id j5sm9091734ejk.87.2020.07.31.05.02.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 05:02:26 -0700 (PDT) From: "Saheed O. Bolarinwa" To: helgaas@kernel.org, "Rafael J. Wysocki" , Len Brown Cc: "Saheed O. Bolarinwa" , bjorn@helgaas.com, skhan@linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: [PATCH v4 07/12] PCI/ACPI: Check if pcie_capability_read_*() reads ~0 Date: Fri, 31 Jul 2020 13:02:35 +0200 Message-Id: <20200731110240.98326-8-refactormyself@gmail.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200731110240.98326-1-refactormyself@gmail.com> References: <20200731110240.98326-1-refactormyself@gmail.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On failure pcie_capability_read_*() sets it's last parameter, val to 0. However, with Patch 12/12, it is possible that val is set to ~0 on failure. This would introduces a bug because (x & x) == (~0 & x). Since ~0 is an invalid value in here, Add extra check for ~0 in the if condition to ensure success or failure. Suggested-by: Bjorn Helgaas Signed-off-by: Saheed O. Bolarinwa --- drivers/pci/pci-acpi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index 7224b1e5f2a8..873b005947e4 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -253,7 +253,7 @@ static bool pcie_root_rcb_set(struct pci_dev *dev) return false; pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); - if (lnkctl & PCI_EXP_LNKCTL_RCB) + if ((lnkctl != (u16)~0) && (lnkctl & PCI_EXP_LNKCTL_RCB)) return true; return false; @@ -797,7 +797,7 @@ bool pciehp_is_native(struct pci_dev *bridge) return false; pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); - if (!(slot_cap & PCI_EXP_SLTCAP_HPC)) + if ((slot_cap == (u32)~0) || !(slot_cap & PCI_EXP_SLTCAP_HPC)) return false; if (pcie_ports_native)