The error-handling pathways in usb_add_gadget_udc_release() are messed up. Aside from the uninformative statement labels, they can deallocate the udc structure after calling put_device(), which is a double-free. This was observed by KASAN in automatic testing. This patch cleans up the routine. It preserves the requirement that when any failure occurs, we call put_device(&gadget->dev). Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> CC: <stable@xxxxxxxxxxxxxxx> --- Not having received any feedback on this patch for a while, I have decided to submit it. The problem it fixes is quite obviously a real one, when you look at the existing code. Alan Stern [as1856] drivers/usb/gadget/udc/core.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) Index: usb-4.x/drivers/usb/gadget/udc/core.c =================================================================== --- usb-4.x.orig/drivers/usb/gadget/udc/core.c +++ usb-4.x/drivers/usb/gadget/udc/core.c @@ -1147,11 +1147,7 @@ int usb_add_gadget_udc_release(struct de udc = kzalloc(sizeof(*udc), GFP_KERNEL); if (!udc) - goto err1; - - ret = device_add(&gadget->dev); - if (ret) - goto err2; + goto err_put_gadget; device_initialize(&udc->dev); udc->dev.release = usb_udc_release; @@ -1160,7 +1156,11 @@ int usb_add_gadget_udc_release(struct de udc->dev.parent = parent; ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj)); if (ret) - goto err3; + goto err_put_udc; + + ret = device_add(&gadget->dev); + if (ret) + goto err_put_udc; udc->gadget = gadget; gadget->udc = udc; @@ -1170,7 +1170,7 @@ int usb_add_gadget_udc_release(struct de ret = device_add(&udc->dev); if (ret) - goto err4; + goto err_unlist_udc; usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED); udc->vbus = true; @@ -1178,27 +1178,25 @@ int usb_add_gadget_udc_release(struct de /* pick up one of pending gadget drivers */ ret = check_pending_gadget_drivers(udc); if (ret) - goto err5; + goto err_del_udc; mutex_unlock(&udc_lock); return 0; -err5: + err_del_udc: device_del(&udc->dev); -err4: + err_unlist_udc: list_del(&udc->list); mutex_unlock(&udc_lock); -err3: - put_device(&udc->dev); device_del(&gadget->dev); -err2: - kfree(udc); + err_put_udc: + put_device(&udc->dev); -err1: + err_put_gadget: put_device(&gadget->dev); return ret; } -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
