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From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: skhan@linuxfoundation.org, linux-pci@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org, Stanislaw Gruszka <stf_xl@wp.pl>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Cc: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>,
	Kalle Valo <kvalo@codeaurora.org>
Subject: [PATCH 4/14 v3] iwlegacy: Check the return value of pcie_capability_read_*()
Date: Mon, 13 Jul 2020 19:55:27 +0200	[thread overview]
Message-ID: <20200713175529.29715-3-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 without changing the function's behaviour if the
return value of pcie_capability_read_dword is checked to confirm success.

Check the return value of pcie_capability_read_dword() to ensure success.

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>

---
 drivers/net/wireless/intel/iwlegacy/common.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index 348c17ce72f5..f78e062df572 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -4286,8 +4286,8 @@ il_apm_init(struct il_priv *il)
 	 *    power savings, even without L1.
 	 */
 	if (il->cfg->set_l0s) {
-		pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl);
-		if (lctl & PCI_EXP_LNKCTL_ASPM_L1) {
+		ret = pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl);
+		if (!ret && (lctl & PCI_EXP_LNKCTL_ASPM_L1)) {
 			/* L1-ASPM enabled; disable(!) L0S  */
 			il_set_bit(il, CSR_GIO_REG,
 				   CSR_GIO_REG_VAL_L0S_ENABLED);
-- 
2.18.2


WARNING: multiple messages have this Message-ID (diff)
From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: skhan@linuxfoundation.org, linux-pci@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org, Stanislaw Gruszka <stf_xl@wp.pl>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Cc: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>,
	Kalle Valo <kvalo@codeaurora.org>
Subject: [Linux-kernel-mentees] [PATCH 4/14 v3] iwlegacy: Check the return value of pcie_capability_read_*()
Date: Mon, 13 Jul 2020 19:55:27 +0200	[thread overview]
Message-ID: <20200713175529.29715-3-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 without changing the function's behaviour if the
return value of pcie_capability_read_dword is checked to confirm success.

Check the return value of pcie_capability_read_dword() to ensure success.

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>

---
 drivers/net/wireless/intel/iwlegacy/common.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index 348c17ce72f5..f78e062df572 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -4286,8 +4286,8 @@ il_apm_init(struct il_priv *il)
 	 *    power savings, even without L1.
 	 */
 	if (il->cfg->set_l0s) {
-		pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl);
-		if (lctl & PCI_EXP_LNKCTL_ASPM_L1) {
+		ret = pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl);
+		if (!ret && (lctl & PCI_EXP_LNKCTL_ASPM_L1)) {
 			/* L1-ASPM enabled; disable(!) L0S  */
 			il_set_bit(il, CSR_GIO_REG,
 				   CSR_GIO_REG_VAL_L0S_ENABLED);
-- 
2.18.2

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

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

Thread overview: 20+ 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 ` Saheed O. Bolarinwa [this message]
2020-07-13 17:55   ` [Linux-kernel-mentees] [PATCH 4/14 v3] iwlegacy: " 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
2020-07-14 13:27     ` [Linux-kernel-mentees] " 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
  -- strict thread matches above, loose matches on Subject: below --
2020-07-10 21:20 [PATCH 0/14 v3] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed Olayemi Bolarinwa
     [not found] ` <20200710212026.27136-5-refactormyself@gmail.com>
2020-07-13 13:44   ` [PATCH 4/14 v3] iwlegacy: Check the return value of pcie_capability_read_*() Kalle Valo
2020-07-13 18:02     ` Saheed Bolarinwa

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