@@ -2053,9 +2053,19 @@ static void update_port_device_state(struct usb_device *udev)
if (udev->parent) {
hub = usb_hub_to_struct_hub(udev->parent);
- port_dev = hub->ports[udev->portnum - 1];
- WRITE_ONCE(port_dev->state, udev->state);
- sysfs_notify_dirent(port_dev->state_kn);
+
+ /*
+ * The Link Layer Validation System Driver (lvstest)
+ * has a test step to unbind the hub before running the
+ * rest of the procedure. This triggers hub_disconnect
+ * which will set the hub's maxchild to 0, further
+ * resulting in usb_hub_to_struct_hub returning NULL.
+ */
+ if (hub) {
+ port_dev = hub->ports[udev->portnum - 1];
+ WRITE_ONCE(port_dev->state, udev->state);
+ sysfs_notify_dirent(port_dev->state_kn);
+ }
}
}
Currently, the function update_port_device_state gets the usb_hub from udev->parent by calling usb_hub_to_struct_hub. However, in case the actconfig or the maxchild is 0, the usb_hub would be NULL and upon further accessing to get port_dev would result in null pointer dereference. Fix this by introducing an if check after the usb_hub is populated. Fixes: 83cb2604f641 ("usb: core: add sysfs entry for usb device state") Cc: stable@vger.kernel.org Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com> --- v5: Addressed nit picks in commit and the comment. v4: Fixed minor mistakes in the comment. v3: Re-wrote the comment for better context. v2: Introduced comment for the if check & CC'ed stable. drivers/usb/core/hub.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)