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From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: skhan@linuxfoundation.org, linux-pci@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Cc: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>
Subject: [Linux-kernel-mentees] [PATCH 12/14 v3] PCI/AER: Check the return value of pcie_capability_read_*()
Date: Mon, 13 Jul 2020 19:55:29 +0200	[thread overview]
Message-ID: <20200713175529.29715-5-refactormyself@gmail.com> (raw)
In-Reply-To: <20200713175529.29715-1-refactormyself@gmail.com>

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>
---
 drivers/pci/pcie/aer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 3acf56683915..f4beb47c622c 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -800,6 +800,7 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 	int aer = dev->aer_cap;
 	u32 status, mask;
 	u16 reg16;
+	int ret;
 
 	/*
 	 * When bus id is equal to 0, it might be a bad id
@@ -828,8 +829,8 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 		return false;
 
 	/* Check if AER is enabled */
-	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
-	if (!(reg16 & PCI_EXP_AER_FLAGS))
+	ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
+	if (ret || !(reg16 & PCI_EXP_AER_FLAGS))
 		return false;
 
 	if (!aer)
-- 
2.18.2

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: skhan@linuxfoundation.org, linux-pci@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Cc: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>
Subject: [PATCH 12/14 v3] PCI/AER: Check the return value of pcie_capability_read_*()
Date: Mon, 13 Jul 2020 19:55:29 +0200	[thread overview]
Message-ID: <20200713175529.29715-5-refactormyself@gmail.com> (raw)
In-Reply-To: <20200713175529.29715-1-refactormyself@gmail.com>

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>
---
 drivers/pci/pcie/aer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 3acf56683915..f4beb47c622c 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -800,6 +800,7 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 	int aer = dev->aer_cap;
 	u32 status, mask;
 	u16 reg16;
+	int ret;
 
 	/*
 	 * When bus id is equal to 0, it might be a bad id
@@ -828,8 +829,8 @@ static bool is_error_source(struct pci_dev *dev, struct aer_err_info *e_info)
 		return false;
 
 	/* Check if AER is enabled */
-	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
-	if (!(reg16 & PCI_EXP_AER_FLAGS))
+	ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &reg16);
+	if (ret || !(reg16 & PCI_EXP_AER_FLAGS))
 		return false;
 
 	if (!aer)
-- 
2.18.2


  parent reply	other threads:[~2020-07-13 16:55 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 17:55 [Linux-kernel-mentees] [PATCH 1/14 v3] IB/hfi1: Check the return value of pcie_capability_read_*() Saheed O. Bolarinwa
2020-07-13 17:55 ` Saheed O. Bolarinwa
2020-07-13 17:09 ` [Linux-kernel-mentees] " Jason Gunthorpe
2020-07-13 17:09   ` Jason Gunthorpe
2020-07-13 17:55 ` [Linux-kernel-mentees] [PATCH 3/14 v3] ath9k: " Saheed O. Bolarinwa
2020-07-13 17:55   ` Saheed O. Bolarinwa
2020-07-20 17:09   ` [Linux-kernel-mentees] " Kalle Valo
2020-07-20 17:09   ` Kalle Valo
2020-07-13 17:55 ` [Linux-kernel-mentees] [PATCH 4/14 v3] iwlegacy: " Saheed O. Bolarinwa
2020-07-13 17:55   ` Saheed O. Bolarinwa
2020-07-15 16:47   ` Kalle Valo
2020-07-15 16:47   ` [Linux-kernel-mentees] " 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
2020-07-14 13:27     ` [Linux-kernel-mentees] " Rafael J. Wysocki
2020-07-13 17:55 ` Saheed O. Bolarinwa [this message]
2020-07-13 17:55   ` [PATCH 12/14 v3] PCI/AER: " Saheed O. Bolarinwa

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