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.
Verify dp drvdata is present in sysfs reads and writes before proceeding.
Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: RD Babiera <rdbabiera@xxxxxxxxxx>
---
drivers/usb/typec/altmodes/displayport.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 5a80776c7255..0423326219d8 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -518,6 +518,9 @@ configuration_store(struct device *dev, struct device_attribute *attr,
int con;
int ret = 0;
+ if (!dp)
+ return -ENODEV;
+
con = sysfs_match_string(configurations, buf);
if (con < 0)
return con;
@@ -563,6 +566,9 @@ static ssize_t configuration_show(struct device *dev,
u8 cur;
int i;
+ if (!dp)
+ return -ENODEV;
+
mutex_lock(&dp->lock);
cap = DP_CAP_CAPABILITY(dp->alt->vdo);
@@ -615,6 +621,9 @@ pin_assignment_store(struct device *dev, struct device_attribute *attr,
u32 conf;
int ret;
+ if (!dp)
+ return -ENODEV;
+
ret = sysfs_match_string(pin_assignments, buf);
if (ret < 0)
return ret;
@@ -666,6 +675,9 @@ static ssize_t pin_assignment_show(struct device *dev,
u8 cur;
int i;
+ if (!dp)
+ return -ENODEV;
+
mutex_lock(&dp->lock);
cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
@@ -698,6 +710,9 @@ static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char
{
struct dp_altmode *dp = dev_get_drvdata(dev);
+ if (!dp)
+ return -ENODEV;
+
return sysfs_emit(buf, "%d\n", dp->hpd);
}
static DEVICE_ATTR_RO(hpd);
base-commit: f1a27f081c1fa1eeebf38406e45f29636114470f
--
2.43.0.429.g432eaa2c6b-goog
