| Message ID | 20240229001101.3889432-2-rdbabiera@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] usb: typec: altmodes/displayport: create sysfs nodes as driver's default device attribute group | expand |
On Thu, Feb 29, 2024 at 12:11:02AM +0000, RD Babiera wrote: > The DisplayPort driver's sysfs nodes may be present to the userspace before > typec_altmode_set_drvdata() completes in dp_altmode_probe. This means that > a sysfs read can trigger a NULL pointer error by deferencing dp->hpd in > hpd_show or dp->lock in pin_assignment_show, as dev_get_drvdata() returns > NULL in those cases. > > Remove manual sysfs node creation in favor of adding attribute group as > default for devices bound to the driver. The ATTRIBUTE_GROUPS() macro is > not used here otherwise the path to the sysfs nodes is no longer compliant > with the ABI. > > Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") > Cc: stable@vger.kernel.org > Signed-off-by: RD Babiera <rdbabiera@google.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > --- > Changes from v1: > * Moved sysfs node creation instead of NULL checking dev_get_drvdata(). > Changes from v2: > * Removed manual sysfs node creation, now added as default device group in > driver. > --- > drivers/usb/typec/altmodes/displayport.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/us<F16>b/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c > index 5a80776c7255..94e1b43a862d 100644 > --- a/drivers/usb/typec/altmodes/displayport.c > +++ b/drivers/usb/typec/altmodes/displayport.c > @@ -702,16 +702,21 @@ static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char > } > static DEVICE_ATTR_RO(hpd); > > -static struct attribute *dp_altmode_attrs[] = { > +static struct attribute *displayport_attrs[] = { > &dev_attr_configuration.attr, > &dev_attr_pin_assignment.attr, > &dev_attr_hpd.attr, > NULL > }; > > -static const struct attribute_group dp_altmode_group = { > +static const struct attribute_group displayport_group = { > .name = "displayport", > - .attrs = dp_altmode_attrs, > + .attrs = displayport_attrs, > +}; > + > +static const struct attribute_group *displayport_groups[] = { > + &displayport_group, > + NULL, > }; > > int dp_altmode_probe(struct typec_altmode *alt) > @@ -720,7 +725,6 @@ int dp_altmode_probe(struct typec_altmode *alt) > struct typec_altmode *plug = typec_altmode_get_plug(alt, TYPEC_PLUG_SOP_P); > struct fwnode_handle *fwnode; > struct dp_altmode *dp; > - int ret; > > /* FIXME: Port can only be DFP_U. */ > > @@ -731,10 +735,6 @@ int dp_altmode_probe(struct typec_altmode *alt) > DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo))) > return -ENODEV; > > - ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group); > - if (ret) > - return ret; > - > dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL); > if (!dp) > return -ENOMEM; > @@ -777,7 +777,6 @@ void dp_altmode_remove(struct typec_altmode *alt) > { > struct dp_altmode *dp = typec_altmode_get_drvdata(alt); > > - sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group); > cancel_work_sync(&dp->work); > typec_altmode_put_plug(dp->plug_prime); > > @@ -803,6 +802,7 @@ static struct typec_altmode_driver dp_altmode_driver = { > .driver = { > .name = "typec_displayport", > .owner = THIS_MODULE, > + .dev_groups = displayport_groups, > }, > }; > module_typec_altmode_driver(dp_altmode_driver); > > base-commit: a560a5672826fc1e057068bda93b3d4c98d037a2 > -- > 2.44.0.rc1.240.g4c46232300-goog
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index 5a80776c7255..94e1b43a862d 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -702,16 +702,21 @@ static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char } static DEVICE_ATTR_RO(hpd); -static struct attribute *dp_altmode_attrs[] = { +static struct attribute *displayport_attrs[] = { &dev_attr_configuration.attr, &dev_attr_pin_assignment.attr, &dev_attr_hpd.attr, NULL }; -static const struct attribute_group dp_altmode_group = { +static const struct attribute_group displayport_group = { .name = "displayport", - .attrs = dp_altmode_attrs, + .attrs = displayport_attrs, +}; + +static const struct attribute_group *displayport_groups[] = { + &displayport_group, + NULL, }; int dp_altmode_probe(struct typec_altmode *alt) @@ -720,7 +725,6 @@ int dp_altmode_probe(struct typec_altmode *alt) struct typec_altmode *plug = typec_altmode_get_plug(alt, TYPEC_PLUG_SOP_P); struct fwnode_handle *fwnode; struct dp_altmode *dp; - int ret; /* FIXME: Port can only be DFP_U. */ @@ -731,10 +735,6 @@ int dp_altmode_probe(struct typec_altmode *alt) DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo))) return -ENODEV; - ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group); - if (ret) - return ret; - dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL); if (!dp) return -ENOMEM; @@ -777,7 +777,6 @@ void dp_altmode_remove(struct typec_altmode *alt) { struct dp_altmode *dp = typec_altmode_get_drvdata(alt); - sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group); cancel_work_sync(&dp->work); typec_altmode_put_plug(dp->plug_prime); @@ -803,6 +802,7 @@ static struct typec_altmode_driver dp_altmode_driver = { .driver = { .name = "typec_displayport", .owner = THIS_MODULE, + .dev_groups = displayport_groups, }, }; module_typec_altmode_driver(dp_altmode_driver);
The DisplayPort driver's sysfs nodes may be present to the userspace before typec_altmode_set_drvdata() completes in dp_altmode_probe. This means that a sysfs read can trigger a NULL pointer error by deferencing dp->hpd in hpd_show or dp->lock in pin_assignment_show, as dev_get_drvdata() returns NULL in those cases. Remove manual sysfs node creation in favor of adding attribute group as default for devices bound to the driver. The ATTRIBUTE_GROUPS() macro is not used here otherwise the path to the sysfs nodes is no longer compliant with the ABI. Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") Cc: stable@vger.kernel.org Signed-off-by: RD Babiera <rdbabiera@google.com> --- Changes from v1: * Moved sysfs node creation instead of NULL checking dev_get_drvdata(). Changes from v2: * Removed manual sysfs node creation, now added as default device group in driver. --- drivers/usb/typec/altmodes/displayport.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) base-commit: a560a5672826fc1e057068bda93b3d4c98d037a2