USB: fix invalid memory access in hub_activate()
Commit8520f38099
("USB: change hub initialization sleeps to delayed_work") changed the hub_activate() routine to make part of it run in a workqueue. However, the commit failed to take a reference to the usb_hub structure or to lock the hub interface while doing so. As a result, if a hub is plugged in and quickly unplugged before the work routine can run, the routine will try to access memory that has been deallocated. Or, if the hub is unplugged while the routine is running, the memory may be deallocated while it is in active use. This patch fixes the problem by taking a reference to the usb_hub at the start of hub_activate() and releasing it at the end (when the work is finished), and by locking the hub interface while the work routine is running. It also adds a check at the start of the routine to see if the hub has already been disconnected, in which nothing should be done. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Alexandru Cornea <alexandru.cornea@intel.com> Tested-by: Alexandru Cornea <alexandru.cornea@intel.com> Fixes:8520f38099
("USB: change hub initialization sleeps to delayed_work") CC: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -1035,10 +1035,20 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
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unsigned delay;
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unsigned delay;
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/* Continue a partial initialization */
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/* Continue a partial initialization */
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if (type == HUB_INIT2)
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if (type == HUB_INIT2 || type == HUB_INIT3) {
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goto init2;
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device_lock(hub->intfdev);
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if (type == HUB_INIT3)
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/* Was the hub disconnected while we were waiting? */
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if (hub->disconnected) {
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device_unlock(hub->intfdev);
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kref_put(&hub->kref, hub_release);
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return;
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}
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if (type == HUB_INIT2)
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goto init2;
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goto init3;
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goto init3;
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}
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kref_get(&hub->kref);
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/* The superspeed hub except for root hub has to use Hub Depth
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/* The superspeed hub except for root hub has to use Hub Depth
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* value as an offset into the route string to locate the bits
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* value as an offset into the route string to locate the bits
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@ -1236,6 +1246,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
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queue_delayed_work(system_power_efficient_wq,
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queue_delayed_work(system_power_efficient_wq,
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&hub->init_work,
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&hub->init_work,
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msecs_to_jiffies(delay));
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msecs_to_jiffies(delay));
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device_unlock(hub->intfdev);
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return; /* Continues at init3: below */
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return; /* Continues at init3: below */
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} else {
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} else {
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msleep(delay);
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msleep(delay);
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@ -1257,6 +1268,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
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/* Allow autosuspend if it was suppressed */
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/* Allow autosuspend if it was suppressed */
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if (type <= HUB_INIT3)
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if (type <= HUB_INIT3)
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usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
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usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
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if (type == HUB_INIT2 || type == HUB_INIT3)
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device_unlock(hub->intfdev);
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kref_put(&hub->kref, hub_release);
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}
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}
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/* Implement the continuations for the delays above */
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/* Implement the continuations for the delays above */
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