Hi Sergei,
On 1/9/2024 3:01 PM, Sergei Shtylyov wrote:
On 1/9/24 9:17 AM, Udipto Goswami wrote:
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@xxxxxxxxxxxxxxx
Signed-off-by: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
---
v3: Re-wrote the comment for better context.
v2: Introduced comment for the if check & CC'ed stable.
drivers/usb/core/hub.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index ffd7c99e24a3..6b514546e59b 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2053,9 +2053,23 @@ 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 procedure of unbinding the hub before running
+ * the rest of the procedure. This triggers
+ * hub_disconnect will set the hub's maxchild to 0.
I can't parse this sentence, s/th is missing...
Thanks for the review.
Maybe this would sound better?
"This triggers hub_disconnect which will set hub's maxchild to 0"
+ * This would result usb_hub_to_struct_hub in this
+ * function to return NULL.
"This would result in usb_hub_to_struct_hub in this function
returning NULL", perhaps?
yah sound better. Will take care of it in next version.
Thanks,
-Udipto
