From: "Rafael J. Wysocki" <rafael@kernel.org> To: "Saheed O. Bolarinwa" <refactormyself@gmail.com> Cc: Shuah Khan <skhan@linuxfoundation.org>, ACPI Devel Maling List <linux-acpi@vger.kernel.org>, Linux PCI <linux-pci@vger.kernel.org>, linux-kernel-mentees@lists.linuxfoundation.org, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 8/14 v3] PCI/ACPI: Check the return value of pcie_capability_read_*() Date: Tue, 14 Jul 2020 15:27:38 +0200 [thread overview] Message-ID: <CAJZ5v0gDwtZ+oYSrj_Ta56QPSeW3OSq4XHkiubOHr4xki7muPw@mail.gmail.com> (raw) In-Reply-To: <20200713175529.29715-4-refactormyself@gmail.com> On Mon, Jul 13, 2020 at 6:55 PM Saheed O. Bolarinwa <refactormyself@gmail.com> wrote: > > From: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> > > On failure pcie_capability_read_dword() sets it's last parameter, > val to 0. > However, with Patch 14/14, it is possible that val is set to ~0 on > failure. This would introduce a bug because (x & x) == (~0 & x). > > This bug can be avoided if the return value of pcie_capability_read_word > is checked to confirm success. > > Check the return value of pcie_capability_read_word() to ensure success. > > Suggested-by: Bjorn Helgaas <bjorn@helgaas.com> > Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/pci/pci-acpi.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index 7224b1e5f2a8..39eb816bc3b8 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -248,12 +248,13 @@ static bool pcie_root_rcb_set(struct pci_dev *dev) > { > struct pci_dev *rp = pcie_find_root_port(dev); > u16 lnkctl; > + int ret; > > if (!rp) > return false; > > - pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > - if (lnkctl & PCI_EXP_LNKCTL_RCB) > + ret = pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > + if (!ret && (lnkctl & PCI_EXP_LNKCTL_RCB)) > return true; > > return false; > @@ -792,12 +793,13 @@ bool pciehp_is_native(struct pci_dev *bridge) > { > const struct pci_host_bridge *host; > u32 slot_cap; > + int ret; > > if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) > return false; > > - pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > - if (!(slot_cap & PCI_EXP_SLTCAP_HPC)) > + ret = pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > + if (ret || !(slot_cap & PCI_EXP_SLTCAP_HPC)) > return false; > > if (pcie_ports_native) > -- > 2.18.2 >
WARNING: multiple messages have this Message-ID (diff)
From: "Rafael J. Wysocki" <rafael@kernel.org> To: "Saheed O. Bolarinwa" <refactormyself@gmail.com> Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>, Linux PCI <linux-pci@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [PATCH 8/14 v3] PCI/ACPI: Check the return value of pcie_capability_read_*() Date: Tue, 14 Jul 2020 15:27:38 +0200 [thread overview] Message-ID: <CAJZ5v0gDwtZ+oYSrj_Ta56QPSeW3OSq4XHkiubOHr4xki7muPw@mail.gmail.com> (raw) In-Reply-To: <20200713175529.29715-4-refactormyself@gmail.com> On Mon, Jul 13, 2020 at 6:55 PM Saheed O. Bolarinwa <refactormyself@gmail.com> wrote: > > From: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> > > On failure pcie_capability_read_dword() sets it's last parameter, > val to 0. > However, with Patch 14/14, it is possible that val is set to ~0 on > failure. This would introduce a bug because (x & x) == (~0 & x). > > This bug can be avoided if the return value of pcie_capability_read_word > is checked to confirm success. > > Check the return value of pcie_capability_read_word() to ensure success. > > Suggested-by: Bjorn Helgaas <bjorn@helgaas.com> > Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/pci/pci-acpi.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index 7224b1e5f2a8..39eb816bc3b8 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -248,12 +248,13 @@ static bool pcie_root_rcb_set(struct pci_dev *dev) > { > struct pci_dev *rp = pcie_find_root_port(dev); > u16 lnkctl; > + int ret; > > if (!rp) > return false; > > - pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > - if (lnkctl & PCI_EXP_LNKCTL_RCB) > + ret = pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > + if (!ret && (lnkctl & PCI_EXP_LNKCTL_RCB)) > return true; > > return false; > @@ -792,12 +793,13 @@ bool pciehp_is_native(struct pci_dev *bridge) > { > const struct pci_host_bridge *host; > u32 slot_cap; > + int ret; > > if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) > return false; > > - pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > - if (!(slot_cap & PCI_EXP_SLTCAP_HPC)) > + ret = pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > + if (ret || !(slot_cap & PCI_EXP_SLTCAP_HPC)) > return false; > > if (pcie_ports_native) > -- > 2.18.2 > _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
next prev parent reply other threads:[~2020-07-14 13:27 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-13 17:55 [PATCH 1/14 v3] IB/hfi1: Check the return value of pcie_capability_read_*() Saheed O. Bolarinwa 2020-07-13 17:55 ` [Linux-kernel-mentees] " Saheed O. Bolarinwa 2020-07-13 17:09 ` Jason Gunthorpe 2020-07-13 17:09 ` [Linux-kernel-mentees] " Jason Gunthorpe 2020-07-13 17:55 ` [PATCH 3/14 v3] ath9k: " Saheed O. Bolarinwa 2020-07-13 17:55 ` [Linux-kernel-mentees] " Saheed O. Bolarinwa 2020-07-20 17:09 ` Kalle Valo 2020-07-20 17:09 ` [Linux-kernel-mentees] " Kalle Valo 2020-07-13 17:55 ` [PATCH 4/14 v3] iwlegacy: " Saheed O. Bolarinwa 2020-07-13 17:55 ` [Linux-kernel-mentees] " Saheed O. Bolarinwa 2020-07-15 16:47 ` Kalle Valo 2020-07-15 16:47 ` Kalle Valo 2020-07-13 17:55 ` [PATCH 8/14 v3] PCI/ACPI: " Saheed O. Bolarinwa 2020-07-13 17:55 ` [Linux-kernel-mentees] " Saheed O. Bolarinwa 2020-07-14 13:27 ` Rafael J. Wysocki [this message] 2020-07-14 13:27 ` Rafael J. Wysocki 2020-07-13 17:55 ` [PATCH 12/14 v3] PCI/AER: " Saheed O. Bolarinwa 2020-07-13 17:55 ` [Linux-kernel-mentees] " Saheed O. Bolarinwa
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