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From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: helgaas@kernel.org, Russell Currey <ruscur@russell.cc>,
	Sam Bobroff <sbobroff@linux.ibm.com>,
	"Oliver O'Halloran" <oohall@gmail.com>
Cc: "Saheed O. Bolarinwa" <refactormyself@gmail.com>,
	bjorn@helgaas.com, skhan@linuxfoundation.org,
	linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 10/12] PCI/AER: Check if pcie_capability_read_*() reads ~0
Date: Fri, 31 Jul 2020 13:43:27 +0200
Message-ID: <20200731114329.100848-3-refactormyself@gmail.com> (raw)
In-Reply-To: <20200731114329.100848-1-refactormyself@gmail.com>

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 introduce a bug because
(x & x) == (~0 & x).

Since ~0 is an invalid value in here,

Add extra check for ~0 to the if condition to confirm failure.

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
---
 drivers/pci/pcie/aer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 3acf56683915..dbeabc370efc 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -829,7 +829,7 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 
 	/* Check if AER is enabled */
 	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
-	if (!(reg16 & PCI_EXP_AER_FLAGS))
+	if ((reg16 == (u16)~0) || !(reg16 & PCI_EXP_AER_FLAGS))
 		return false;
 
 	if (!aer)
-- 
2.18.4


  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 11:43 [PATCH v4 08/12] PCI: " Saheed O. Bolarinwa
2020-07-31 11:43 ` [PATCH v4 09/12] PCI/PM: " Saheed O. Bolarinwa
2020-07-31 11:43 ` Saheed O. Bolarinwa [this message]
2020-07-31 11:43 ` [PATCH v4 11/12] PCI/ASPM: " Saheed O. Bolarinwa
2020-07-31 11:43 ` [PATCH v4 12/12] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed O. Bolarinwa

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