6.6-stable review patch. If anyone has any objections, please let me know.
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From: Udipto Goswami quic_ugoswami@quicinc.com
commit 12783c0b9e2c7915a50d5ec829630ff2da50472c upstream.
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 Reviewed-by: Alan Stern stern@rowland.harvard.edu Link: https://lore.kernel.org/r/20240110095814.7626-1-quic_ugoswami@quicinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/core/hub.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
--- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2047,9 +2047,19 @@ static void update_port_device_state(str
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); + } } }