The extcon_get_extcon_dev() function returns error pointers on error
and NULL when it's a -EPROBE_DEFER defer situation. There are eight
callers and only two of them handled this correctly. In the other
callers an error pointer return would lead to a crash.
What prevents crashes is that errors can only happen in the case of
a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
eight callers use the Kconfig to either depend on or select
CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
Signed-off-by: Dan Carpenter <[email protected]>
---
The two callers where the drivers can be built without CONFIG_EXTCON
are TYPEC_FUSB302 and CHARGER_MAX8997.
If we apply this patch, it might be a good idea to send it to -stable
so that backported code that relies on handling error pointers does
not break silently.
drivers/extcon/extcon.c | 2 +-
drivers/power/supply/axp288_charger.c | 17 ++++++++++-------
drivers/power/supply/charger-manager.c | 7 ++-----
drivers/power/supply/max8997_charger.c | 10 +++++-----
drivers/usb/dwc3/drd.c | 9 ++-------
drivers/usb/phy/phy-omap-otg.c | 4 ++--
drivers/usb/typec/tcpm/fusb302.c | 4 ++--
drivers/extcon/extcon-axp288.c | 4 ++--
8 files changed, 26 insertions(+), 31 deletions(-)
diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index e7a9561a826d..a35e99928807 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -876,7 +876,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
if (!strcmp(sd->name, extcon_name))
goto out;
}
- sd = NULL;
+ sd = ERR_PTR(-EPROBE_DEFER);
out:
mutex_unlock(&extcon_dev_list_lock);
return sd;
diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c
index ec41f6cd3f93..4acfeb52a44e 100644
--- a/drivers/power/supply/axp288_charger.c
+++ b/drivers/power/supply/axp288_charger.c
@@ -848,17 +848,20 @@ static int axp288_charger_probe(struct platform_device *pdev)
info->regmap_irqc = axp20x->regmap_irqc;
info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME);
- if (info->cable.edev == NULL) {
- dev_dbg(dev, "%s is not ready, probe deferred\n",
- AXP288_EXTCON_DEV_NAME);
- return -EPROBE_DEFER;
+ if (IS_ERR(info->cable.edev)) {
+ dev_err_probe(dev, PTR_ERR(info->cable.edev),
+ "extcon_get_extcon_dev(%s) failed\n",
+ AXP288_EXTCON_DEV_NAME);
+ return PTR_ERR(info->cable.edev);
}
if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) {
info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME);
- if (info->otg.cable == NULL) {
- dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n");
- return -EPROBE_DEFER;
+ if (IS_ERR(info->otg.cable)) {
+ dev_err_probe(dev, PTR_ERR(info->otg.cable),
+ "extcon_get_extcon_dev(%s) failed\n",
+ USB_HOST_EXTCON_NAME);
+ return PTR_ERR(info->otg.cable);
}
dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n");
}
diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
index d67edb760c94..92db79400a6a 100644
--- a/drivers/power/supply/charger-manager.c
+++ b/drivers/power/supply/charger-manager.c
@@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm,
cable->nb.notifier_call = charger_extcon_notifier;
cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name);
- if (IS_ERR_OR_NULL(cable->extcon_dev)) {
+ if (IS_ERR(cable->extcon_dev)) {
pr_err("Cannot find extcon_dev for %s (cable: %s)\n",
cable->extcon_name, cable->name);
- if (cable->extcon_dev == NULL)
- return -EPROBE_DEFER;
- else
- return PTR_ERR(cable->extcon_dev);
+ return PTR_ERR(cable->extcon_dev);
}
for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) {
diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c
index 25207fe2aa68..634658adf313 100644
--- a/drivers/power/supply/max8997_charger.c
+++ b/drivers/power/supply/max8997_charger.c
@@ -248,13 +248,13 @@ static int max8997_battery_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "couldn't get charger regulator\n");
}
charger->edev = extcon_get_extcon_dev("max8997-muic");
- if (IS_ERR_OR_NULL(charger->edev)) {
- if (!charger->edev)
- return -EPROBE_DEFER;
- dev_info(charger->dev, "couldn't get extcon device\n");
+ if (IS_ERR(charger->edev)) {
+ dev_err_probe(charger->dev, PTR_ERR(charger->edev),
+ "couldn't get extcon device: max8997-muic\n");
+ return PTR_ERR(charger->edev);
}
- if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) {
+ if (!IS_ERR(charger->reg)) {
INIT_WORK(&charger->extcon_work, max8997_battery_extcon_evt_worker);
ret = devm_add_action(&pdev->dev, max8997_battery_extcon_evt_stop_work, charger);
if (ret) {
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index d7f76835137f..a490f79131c1 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
* This device property is for kernel internal use only and
* is expected to be set by the glue code.
*/
- if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
- edev = extcon_get_extcon_dev(name);
- if (!edev)
- return ERR_PTR(-EPROBE_DEFER);
-
- return edev;
- }
+ if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
+ return extcon_get_extcon_dev(name);
/*
* Try to get an extcon device from the USB PHY controller's "port"
diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c
index ee0863c6553e..6e6ef8c0bc7e 100644
--- a/drivers/usb/phy/phy-omap-otg.c
+++ b/drivers/usb/phy/phy-omap-otg.c
@@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev)
return -ENODEV;
extcon = extcon_get_extcon_dev(config->extcon);
- if (!extcon)
- return -EPROBE_DEFER;
+ if (IS_ERR(extcon))
+ return PTR_ERR(extcon);
otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL);
if (!otg_dev)
diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index 7a2a17866a82..8594b59bd527 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
*/
if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
chip->extcon = extcon_get_extcon_dev(name);
- if (!chip->extcon)
- return -EPROBE_DEFER;
+ if (IS_ERR(chip->extcon))
+ return PTR_ERR(chip->extcon);
}
chip->vbus = devm_regulator_get(chip->dev, "vbus");
diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
index 7c6d5857ff25..180be768c215 100644
--- a/drivers/extcon/extcon-axp288.c
+++ b/drivers/extcon/extcon-axp288.c
@@ -394,8 +394,8 @@ static int axp288_extcon_probe(struct platform_device *pdev)
if (adev) {
info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev));
put_device(&adev->dev);
- if (!info->id_extcon)
- return -EPROBE_DEFER;
+ if (IS_ERR(info->id_extcon))
+ return PTR_ERR(info->id_extcon);
dev_info(dev, "controlling USB role\n");
} else {
--
2.20.1
Hi,
On Thu, Nov 18, 2021 at 02:32:22PM +0300, Dan Carpenter wrote:
> The extcon_get_extcon_dev() function returns error pointers on error
> and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> callers and only two of them handled this correctly. In the other
> callers an error pointer return would lead to a crash.
>
> What prevents crashes is that errors can only happen in the case of
> a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> eight callers use the Kconfig to either depend on or select
> CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> The two callers where the drivers can be built without CONFIG_EXTCON
> are TYPEC_FUSB302 and CHARGER_MAX8997.
>
> If we apply this patch, it might be a good idea to send it to -stable
> so that backported code that relies on handling error pointers does
> not break silently.
>
> drivers/extcon/extcon.c | 2 +-
> drivers/power/supply/axp288_charger.c | 17 ++++++++++-------
> drivers/power/supply/charger-manager.c | 7 ++-----
> drivers/power/supply/max8997_charger.c | 10 +++++-----
> drivers/usb/dwc3/drd.c | 9 ++-------
> drivers/usb/phy/phy-omap-otg.c | 4 ++--
> drivers/usb/typec/tcpm/fusb302.c | 4 ++--
> drivers/extcon/extcon-axp288.c | 4 ++--
> 8 files changed, 26 insertions(+), 31 deletions(-)
Acked-by: Sebastian Reichel <[email protected]> # for power-supply
-- Sebastian
>
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index e7a9561a826d..a35e99928807 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -876,7 +876,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
> if (!strcmp(sd->name, extcon_name))
> goto out;
> }
> - sd = NULL;
> + sd = ERR_PTR(-EPROBE_DEFER);
> out:
> mutex_unlock(&extcon_dev_list_lock);
> return sd;
> diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c
> index ec41f6cd3f93..4acfeb52a44e 100644
> --- a/drivers/power/supply/axp288_charger.c
> +++ b/drivers/power/supply/axp288_charger.c
> @@ -848,17 +848,20 @@ static int axp288_charger_probe(struct platform_device *pdev)
> info->regmap_irqc = axp20x->regmap_irqc;
>
> info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME);
> - if (info->cable.edev == NULL) {
> - dev_dbg(dev, "%s is not ready, probe deferred\n",
> - AXP288_EXTCON_DEV_NAME);
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->cable.edev)) {
> + dev_err_probe(dev, PTR_ERR(info->cable.edev),
> + "extcon_get_extcon_dev(%s) failed\n",
> + AXP288_EXTCON_DEV_NAME);
> + return PTR_ERR(info->cable.edev);
> }
>
> if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) {
> info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME);
> - if (info->otg.cable == NULL) {
> - dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n");
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->otg.cable)) {
> + dev_err_probe(dev, PTR_ERR(info->otg.cable),
> + "extcon_get_extcon_dev(%s) failed\n",
> + USB_HOST_EXTCON_NAME);
> + return PTR_ERR(info->otg.cable);
> }
> dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n");
> }
> diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
> index d67edb760c94..92db79400a6a 100644
> --- a/drivers/power/supply/charger-manager.c
> +++ b/drivers/power/supply/charger-manager.c
> @@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm,
> cable->nb.notifier_call = charger_extcon_notifier;
>
> cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name);
> - if (IS_ERR_OR_NULL(cable->extcon_dev)) {
> + if (IS_ERR(cable->extcon_dev)) {
> pr_err("Cannot find extcon_dev for %s (cable: %s)\n",
> cable->extcon_name, cable->name);
> - if (cable->extcon_dev == NULL)
> - return -EPROBE_DEFER;
> - else
> - return PTR_ERR(cable->extcon_dev);
> + return PTR_ERR(cable->extcon_dev);
> }
>
> for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) {
> diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c
> index 25207fe2aa68..634658adf313 100644
> --- a/drivers/power/supply/max8997_charger.c
> +++ b/drivers/power/supply/max8997_charger.c
> @@ -248,13 +248,13 @@ static int max8997_battery_probe(struct platform_device *pdev)
> dev_info(&pdev->dev, "couldn't get charger regulator\n");
> }
> charger->edev = extcon_get_extcon_dev("max8997-muic");
> - if (IS_ERR_OR_NULL(charger->edev)) {
> - if (!charger->edev)
> - return -EPROBE_DEFER;
> - dev_info(charger->dev, "couldn't get extcon device\n");
> + if (IS_ERR(charger->edev)) {
> + dev_err_probe(charger->dev, PTR_ERR(charger->edev),
> + "couldn't get extcon device: max8997-muic\n");
> + return PTR_ERR(charger->edev);
> }
>
> - if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) {
> + if (!IS_ERR(charger->reg)) {
> INIT_WORK(&charger->extcon_work, max8997_battery_extcon_evt_worker);
> ret = devm_add_action(&pdev->dev, max8997_battery_extcon_evt_stop_work, charger);
> if (ret) {
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index d7f76835137f..a490f79131c1 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> * This device property is for kernel internal use only and
> * is expected to be set by the glue code.
> */
> - if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> - edev = extcon_get_extcon_dev(name);
> - if (!edev)
> - return ERR_PTR(-EPROBE_DEFER);
> -
> - return edev;
> - }
> + if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
> + return extcon_get_extcon_dev(name);
>
> /*
> * Try to get an extcon device from the USB PHY controller's "port"
> diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c
> index ee0863c6553e..6e6ef8c0bc7e 100644
> --- a/drivers/usb/phy/phy-omap-otg.c
> +++ b/drivers/usb/phy/phy-omap-otg.c
> @@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev)
> return -ENODEV;
>
> extcon = extcon_get_extcon_dev(config->extcon);
> - if (!extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(extcon))
> + return PTR_ERR(extcon);
>
> otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL);
> if (!otg_dev)
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 7a2a17866a82..8594b59bd527 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> */
> if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> chip->extcon = extcon_get_extcon_dev(name);
> - if (!chip->extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(chip->extcon))
> + return PTR_ERR(chip->extcon);
> }
>
> chip->vbus = devm_regulator_get(chip->dev, "vbus");
> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
> index 7c6d5857ff25..180be768c215 100644
> --- a/drivers/extcon/extcon-axp288.c
> +++ b/drivers/extcon/extcon-axp288.c
> @@ -394,8 +394,8 @@ static int axp288_extcon_probe(struct platform_device *pdev)
> if (adev) {
> info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev));
> put_device(&adev->dev);
> - if (!info->id_extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->id_extcon))
> + return PTR_ERR(info->id_extcon);
>
> dev_info(dev, "controlling USB role\n");
> } else {
> --
> 2.20.1
>
Hi,
On 11/18/21 12:32, Dan Carpenter wrote:
> The extcon_get_extcon_dev() function returns error pointers on error
> and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> callers and only two of them handled this correctly. In the other
> callers an error pointer return would lead to a crash.
>
> What prevents crashes is that errors can only happen in the case of
> a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> eight callers use the Kconfig to either depend on or select
> CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
>
> Signed-off-by: Dan Carpenter <[email protected]>
Thanks, patch looks good to me:
Reviewed-by: Hans de Goede <[email protected]>
Regards,
Hans
> ---
> The two callers where the drivers can be built without CONFIG_EXTCON
> are TYPEC_FUSB302 and CHARGER_MAX8997.
>
> If we apply this patch, it might be a good idea to send it to -stable
> so that backported code that relies on handling error pointers does
> not break silently.
>
> drivers/extcon/extcon.c | 2 +-
> drivers/power/supply/axp288_charger.c | 17 ++++++++++-------
> drivers/power/supply/charger-manager.c | 7 ++-----
> drivers/power/supply/max8997_charger.c | 10 +++++-----
> drivers/usb/dwc3/drd.c | 9 ++-------
> drivers/usb/phy/phy-omap-otg.c | 4 ++--
> drivers/usb/typec/tcpm/fusb302.c | 4 ++--
> drivers/extcon/extcon-axp288.c | 4 ++--
> 8 files changed, 26 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index e7a9561a826d..a35e99928807 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -876,7 +876,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
> if (!strcmp(sd->name, extcon_name))
> goto out;
> }
> - sd = NULL;
> + sd = ERR_PTR(-EPROBE_DEFER);
> out:
> mutex_unlock(&extcon_dev_list_lock);
> return sd;
> diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c
> index ec41f6cd3f93..4acfeb52a44e 100644
> --- a/drivers/power/supply/axp288_charger.c
> +++ b/drivers/power/supply/axp288_charger.c
> @@ -848,17 +848,20 @@ static int axp288_charger_probe(struct platform_device *pdev)
> info->regmap_irqc = axp20x->regmap_irqc;
>
> info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME);
> - if (info->cable.edev == NULL) {
> - dev_dbg(dev, "%s is not ready, probe deferred\n",
> - AXP288_EXTCON_DEV_NAME);
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->cable.edev)) {
> + dev_err_probe(dev, PTR_ERR(info->cable.edev),
> + "extcon_get_extcon_dev(%s) failed\n",
> + AXP288_EXTCON_DEV_NAME);
> + return PTR_ERR(info->cable.edev);
> }
>
> if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) {
> info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME);
> - if (info->otg.cable == NULL) {
> - dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n");
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->otg.cable)) {
> + dev_err_probe(dev, PTR_ERR(info->otg.cable),
> + "extcon_get_extcon_dev(%s) failed\n",
> + USB_HOST_EXTCON_NAME);
> + return PTR_ERR(info->otg.cable);
> }
> dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n");
> }
> diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
> index d67edb760c94..92db79400a6a 100644
> --- a/drivers/power/supply/charger-manager.c
> +++ b/drivers/power/supply/charger-manager.c
> @@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm,
> cable->nb.notifier_call = charger_extcon_notifier;
>
> cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name);
> - if (IS_ERR_OR_NULL(cable->extcon_dev)) {
> + if (IS_ERR(cable->extcon_dev)) {
> pr_err("Cannot find extcon_dev for %s (cable: %s)\n",
> cable->extcon_name, cable->name);
> - if (cable->extcon_dev == NULL)
> - return -EPROBE_DEFER;
> - else
> - return PTR_ERR(cable->extcon_dev);
> + return PTR_ERR(cable->extcon_dev);
> }
>
> for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) {
> diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c
> index 25207fe2aa68..634658adf313 100644
> --- a/drivers/power/supply/max8997_charger.c
> +++ b/drivers/power/supply/max8997_charger.c
> @@ -248,13 +248,13 @@ static int max8997_battery_probe(struct platform_device *pdev)
> dev_info(&pdev->dev, "couldn't get charger regulator\n");
> }
> charger->edev = extcon_get_extcon_dev("max8997-muic");
> - if (IS_ERR_OR_NULL(charger->edev)) {
> - if (!charger->edev)
> - return -EPROBE_DEFER;
> - dev_info(charger->dev, "couldn't get extcon device\n");
> + if (IS_ERR(charger->edev)) {
> + dev_err_probe(charger->dev, PTR_ERR(charger->edev),
> + "couldn't get extcon device: max8997-muic\n");
> + return PTR_ERR(charger->edev);
> }
>
> - if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) {
> + if (!IS_ERR(charger->reg)) {
> INIT_WORK(&charger->extcon_work, max8997_battery_extcon_evt_worker);
> ret = devm_add_action(&pdev->dev, max8997_battery_extcon_evt_stop_work, charger);
> if (ret) {
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index d7f76835137f..a490f79131c1 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> * This device property is for kernel internal use only and
> * is expected to be set by the glue code.
> */
> - if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> - edev = extcon_get_extcon_dev(name);
> - if (!edev)
> - return ERR_PTR(-EPROBE_DEFER);
> -
> - return edev;
> - }
> + if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
> + return extcon_get_extcon_dev(name);
>
> /*
> * Try to get an extcon device from the USB PHY controller's "port"
> diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c
> index ee0863c6553e..6e6ef8c0bc7e 100644
> --- a/drivers/usb/phy/phy-omap-otg.c
> +++ b/drivers/usb/phy/phy-omap-otg.c
> @@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev)
> return -ENODEV;
>
> extcon = extcon_get_extcon_dev(config->extcon);
> - if (!extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(extcon))
> + return PTR_ERR(extcon);
>
> otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL);
> if (!otg_dev)
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 7a2a17866a82..8594b59bd527 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> */
> if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> chip->extcon = extcon_get_extcon_dev(name);
> - if (!chip->extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(chip->extcon))
> + return PTR_ERR(chip->extcon);
> }
>
> chip->vbus = devm_regulator_get(chip->dev, "vbus");
> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
> index 7c6d5857ff25..180be768c215 100644
> --- a/drivers/extcon/extcon-axp288.c
> +++ b/drivers/extcon/extcon-axp288.c
> @@ -394,8 +394,8 @@ static int axp288_extcon_probe(struct platform_device *pdev)
> if (adev) {
> info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev));
> put_device(&adev->dev);
> - if (!info->id_extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->id_extcon))
> + return PTR_ERR(info->id_extcon);
>
> dev_info(dev, "controlling USB role\n");
> } else {
>
On Thu, Nov 18, 2021 at 02:32:22PM +0300, Dan Carpenter wrote:
> The extcon_get_extcon_dev() function returns error pointers on error
> and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> callers and only two of them handled this correctly. In the other
> callers an error pointer return would lead to a crash.
>
> What prevents crashes is that errors can only happen in the case of
> a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> eight callers use the Kconfig to either depend on or select
> CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
>
> Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Heikki Krogerus <[email protected]>
> ---
> The two callers where the drivers can be built without CONFIG_EXTCON
> are TYPEC_FUSB302 and CHARGER_MAX8997.
>
> If we apply this patch, it might be a good idea to send it to -stable
> so that backported code that relies on handling error pointers does
> not break silently.
>
> drivers/extcon/extcon.c | 2 +-
> drivers/power/supply/axp288_charger.c | 17 ++++++++++-------
> drivers/power/supply/charger-manager.c | 7 ++-----
> drivers/power/supply/max8997_charger.c | 10 +++++-----
> drivers/usb/dwc3/drd.c | 9 ++-------
> drivers/usb/phy/phy-omap-otg.c | 4 ++--
> drivers/usb/typec/tcpm/fusb302.c | 4 ++--
> drivers/extcon/extcon-axp288.c | 4 ++--
> 8 files changed, 26 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index e7a9561a826d..a35e99928807 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -876,7 +876,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
> if (!strcmp(sd->name, extcon_name))
> goto out;
> }
> - sd = NULL;
> + sd = ERR_PTR(-EPROBE_DEFER);
> out:
> mutex_unlock(&extcon_dev_list_lock);
> return sd;
> diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c
> index ec41f6cd3f93..4acfeb52a44e 100644
> --- a/drivers/power/supply/axp288_charger.c
> +++ b/drivers/power/supply/axp288_charger.c
> @@ -848,17 +848,20 @@ static int axp288_charger_probe(struct platform_device *pdev)
> info->regmap_irqc = axp20x->regmap_irqc;
>
> info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME);
> - if (info->cable.edev == NULL) {
> - dev_dbg(dev, "%s is not ready, probe deferred\n",
> - AXP288_EXTCON_DEV_NAME);
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->cable.edev)) {
> + dev_err_probe(dev, PTR_ERR(info->cable.edev),
> + "extcon_get_extcon_dev(%s) failed\n",
> + AXP288_EXTCON_DEV_NAME);
> + return PTR_ERR(info->cable.edev);
> }
>
> if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) {
> info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME);
> - if (info->otg.cable == NULL) {
> - dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n");
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->otg.cable)) {
> + dev_err_probe(dev, PTR_ERR(info->otg.cable),
> + "extcon_get_extcon_dev(%s) failed\n",
> + USB_HOST_EXTCON_NAME);
> + return PTR_ERR(info->otg.cable);
> }
> dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n");
> }
> diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
> index d67edb760c94..92db79400a6a 100644
> --- a/drivers/power/supply/charger-manager.c
> +++ b/drivers/power/supply/charger-manager.c
> @@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm,
> cable->nb.notifier_call = charger_extcon_notifier;
>
> cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name);
> - if (IS_ERR_OR_NULL(cable->extcon_dev)) {
> + if (IS_ERR(cable->extcon_dev)) {
> pr_err("Cannot find extcon_dev for %s (cable: %s)\n",
> cable->extcon_name, cable->name);
> - if (cable->extcon_dev == NULL)
> - return -EPROBE_DEFER;
> - else
> - return PTR_ERR(cable->extcon_dev);
> + return PTR_ERR(cable->extcon_dev);
> }
>
> for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) {
> diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c
> index 25207fe2aa68..634658adf313 100644
> --- a/drivers/power/supply/max8997_charger.c
> +++ b/drivers/power/supply/max8997_charger.c
> @@ -248,13 +248,13 @@ static int max8997_battery_probe(struct platform_device *pdev)
> dev_info(&pdev->dev, "couldn't get charger regulator\n");
> }
> charger->edev = extcon_get_extcon_dev("max8997-muic");
> - if (IS_ERR_OR_NULL(charger->edev)) {
> - if (!charger->edev)
> - return -EPROBE_DEFER;
> - dev_info(charger->dev, "couldn't get extcon device\n");
> + if (IS_ERR(charger->edev)) {
> + dev_err_probe(charger->dev, PTR_ERR(charger->edev),
> + "couldn't get extcon device: max8997-muic\n");
> + return PTR_ERR(charger->edev);
> }
>
> - if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) {
> + if (!IS_ERR(charger->reg)) {
> INIT_WORK(&charger->extcon_work, max8997_battery_extcon_evt_worker);
> ret = devm_add_action(&pdev->dev, max8997_battery_extcon_evt_stop_work, charger);
> if (ret) {
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index d7f76835137f..a490f79131c1 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> * This device property is for kernel internal use only and
> * is expected to be set by the glue code.
> */
> - if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> - edev = extcon_get_extcon_dev(name);
> - if (!edev)
> - return ERR_PTR(-EPROBE_DEFER);
> -
> - return edev;
> - }
> + if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
> + return extcon_get_extcon_dev(name);
>
> /*
> * Try to get an extcon device from the USB PHY controller's "port"
> diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c
> index ee0863c6553e..6e6ef8c0bc7e 100644
> --- a/drivers/usb/phy/phy-omap-otg.c
> +++ b/drivers/usb/phy/phy-omap-otg.c
> @@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev)
> return -ENODEV;
>
> extcon = extcon_get_extcon_dev(config->extcon);
> - if (!extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(extcon))
> + return PTR_ERR(extcon);
>
> otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL);
> if (!otg_dev)
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 7a2a17866a82..8594b59bd527 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> */
> if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> chip->extcon = extcon_get_extcon_dev(name);
> - if (!chip->extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(chip->extcon))
> + return PTR_ERR(chip->extcon);
> }
>
> chip->vbus = devm_regulator_get(chip->dev, "vbus");
> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
> index 7c6d5857ff25..180be768c215 100644
> --- a/drivers/extcon/extcon-axp288.c
> +++ b/drivers/extcon/extcon-axp288.c
> @@ -394,8 +394,8 @@ static int axp288_extcon_probe(struct platform_device *pdev)
> if (adev) {
> info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev));
> put_device(&adev->dev);
> - if (!info->id_extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(info->id_extcon))
> + return PTR_ERR(info->id_extcon);
>
> dev_info(dev, "controlling USB role\n");
> } else {
> --
> 2.20.1
--
heikki
On 11/18/21 3:32 AM, Dan Carpenter wrote:
> The extcon_get_extcon_dev() function returns error pointers on error
> and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> callers and only two of them handled this correctly. In the other
> callers an error pointer return would lead to a crash.
>
> What prevents crashes is that errors can only happen in the case of
> a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> eight callers use the Kconfig to either depend on or select
> CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> The two callers where the drivers can be built without CONFIG_EXTCON
> are TYPEC_FUSB302 and CHARGER_MAX8997.
>
[ ... ]
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 7a2a17866a82..8594b59bd527 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> */
> if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> chip->extcon = extcon_get_extcon_dev(name);
> - if (!chip->extcon)
> - return -EPROBE_DEFER;
> + if (IS_ERR(chip->extcon))
> + return PTR_ERR(chip->extcon);
Why does the code not need to return -EPROBE_DEFER ? The description states
that NULL is returned in that situation. Doesn't that mean that defer situations
are no longer handled with this patch in place ?
Also, with this patch in place, the code will no longer work if extcon is disabled,
because extcon_get_extcon_dev() will return -ENODEV and the above code will bail out.
The behavior of the code wasn't optimal in that case (it would wait until timeout
in tcpm_get_current_limit() before returning), but at least it didn't fail.
Thanks,
Guenter
On Thu, Nov 18, 2021 at 06:22:58AM -0800, Guenter Roeck wrote:
> On 11/18/21 3:32 AM, Dan Carpenter wrote:
> > The extcon_get_extcon_dev() function returns error pointers on error
> > and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> > callers and only two of them handled this correctly. In the other
> > callers an error pointer return would lead to a crash.
> >
> > What prevents crashes is that errors can only happen in the case of
> > a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> > eight callers use the Kconfig to either depend on or select
> > CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
> >
> > Signed-off-by: Dan Carpenter <[email protected]>
> > ---
> > The two callers where the drivers can be built without CONFIG_EXTCON
> > are TYPEC_FUSB302 and CHARGER_MAX8997.
> >
> [ ... ]
> > diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> > index 7a2a17866a82..8594b59bd527 100644
> > --- a/drivers/usb/typec/tcpm/fusb302.c
> > +++ b/drivers/usb/typec/tcpm/fusb302.c
> > @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> > */
> > if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> > chip->extcon = extcon_get_extcon_dev(name);
> > - if (!chip->extcon)
> > - return -EPROBE_DEFER;
> > + if (IS_ERR(chip->extcon))
> > + return PTR_ERR(chip->extcon);
>
> Why does the code not need to return -EPROBE_DEFER ? The description states
> that NULL is returned in that situation. Doesn't that mean that defer situations
> are no longer handled with this patch in place ?
I'm not sure I understand what you are saying here. In the original
code, extcon_get_extcon_dev() would return NULL and relied on the
callers to change NULL into a -EPROBE_DEFER. If extcon_get_extcon_dev()
returned ERR_PTR(-EINVAL) (which is impossible as mentioned) the it
would lead to a crash.
In the new code, the extcon_get_extcon_dev() function returns
-EPROBE_DEFER directly so the caller code is much simpler.
>
> Also, with this patch in place, the code will no longer work if extcon is disabled,
> because extcon_get_extcon_dev() will return -ENODEV and the above code will bail out.
> The behavior of the code wasn't optimal in that case (it would wait until timeout
> in tcpm_get_current_limit() before returning), but at least it didn't fail.
Huh. You are right. Initialy I thought that tcpm_get_current_limit()
would crash. This is one of the two drivers which I mentioned that can
be built without CONFIG_EXTCON.
I will modify the version of extcon_get_extcon_dev() where CONFIG_EXTCON
is disabled to return NULL. That is the standard/correct way to write
these. That will turn tcpm_get_current_limit() into a no-op.
A belt and suspenders approach might be to modify the Kconfig so this
driver selects CONFIG_EXTCON.
regards,
dan carpenter
On Thu, Nov 18, 2021 at 05:51:35PM +0300, Dan Carpenter wrote:
> On Thu, Nov 18, 2021 at 06:22:58AM -0800, Guenter Roeck wrote:
> > On 11/18/21 3:32 AM, Dan Carpenter wrote:
> > > The extcon_get_extcon_dev() function returns error pointers on error
> > > and NULL when it's a -EPROBE_DEFER defer situation. There are eight
> > > callers and only two of them handled this correctly. In the other
> > > callers an error pointer return would lead to a crash.
> > >
> > > What prevents crashes is that errors can only happen in the case of
> > > a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
> > > eight callers use the Kconfig to either depend on or select
> > > CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.
> > >
> > > Signed-off-by: Dan Carpenter <[email protected]>
> > > ---
> > > The two callers where the drivers can be built without CONFIG_EXTCON
> > > are TYPEC_FUSB302 and CHARGER_MAX8997.
> > >
> > [ ... ]
> > > diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> > > index 7a2a17866a82..8594b59bd527 100644
> > > --- a/drivers/usb/typec/tcpm/fusb302.c
> > > +++ b/drivers/usb/typec/tcpm/fusb302.c
> > > @@ -1706,8 +1706,8 @@ static int fusb302_probe(struct i2c_client *client,
> > > */
> > > if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
> > > chip->extcon = extcon_get_extcon_dev(name);
> > > - if (!chip->extcon)
> > > - return -EPROBE_DEFER;
> > > + if (IS_ERR(chip->extcon))
> > > + return PTR_ERR(chip->extcon);
> >
> > Why does the code not need to return -EPROBE_DEFER ? The description states
> > that NULL is returned in that situation. Doesn't that mean that defer situations
> > are no longer handled with this patch in place ?
>
> I'm not sure I understand what you are saying here. In the original
> code, extcon_get_extcon_dev() would return NULL and relied on the
> callers to change NULL into a -EPROBE_DEFER. If extcon_get_extcon_dev()
> returned ERR_PTR(-EINVAL) (which is impossible as mentioned) the it
> would lead to a crash.
>
> In the new code, the extcon_get_extcon_dev() function returns
> -EPROBE_DEFER directly so the caller code is much simpler.
>
Misunderstanding on my side. I didn't get that extcon_get_extcon_dev()
now returns -EPROBE_DEFER.
> >
> > Also, with this patch in place, the code will no longer work if extcon is disabled,
> > because extcon_get_extcon_dev() will return -ENODEV and the above code will bail out.
> > The behavior of the code wasn't optimal in that case (it would wait until timeout
> > in tcpm_get_current_limit() before returning), but at least it didn't fail.
>
> Huh. You are right. Initialy I thought that tcpm_get_current_limit()
> would crash. This is one of the two drivers which I mentioned that can
> be built without CONFIG_EXTCON.
>
> I will modify the version of extcon_get_extcon_dev() where CONFIG_EXTCON
> is disabled to return NULL. That is the standard/correct way to write
> these. That will turn tcpm_get_current_limit() into a no-op.
>
> A belt and suspenders approach might be to modify the Kconfig so this
> driver selects CONFIG_EXTCON.
>
That would pull in unnecessary extra code, though, if the driver is supposed
to be able to work without it.
Thanks,
Guenter
> regards,
> dan carpenter
>