| Message ID | 20211118113026.GG1147@kili (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | extcon: fix extcon_get_extcon_dev() error handling | expand |
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 <dan.carpenter@oracle.com> > --- > 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 <sebastian.reichel@collabora.com> # 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 <dan.carpenter@oracle.com> Thanks, patch looks good to me: Reviewed-by: Hans de Goede <hdegoede@redhat.com> 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 <dan.carpenter@oracle.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > --- > 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
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 <dan.carpenter@oracle.com> > --- > 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 <dan.carpenter@oracle.com> > > --- > > 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 <dan.carpenter@oracle.com> > > > --- > > > 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 >
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 {
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 <dan.carpenter@oracle.com> --- 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(-)