@@ -104,6 +104,7 @@ EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem);
#define HUB_DEBOUNCE_STEP 25
#define HUB_DEBOUNCE_STABLE 100
+static void hub_release(struct kref *kref);
static int usb_reset_and_verify_device(struct usb_device *udev);
static inline char *portspeed(struct usb_hub *hub, int portstatus)
@@ -1027,10 +1028,20 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
unsigned delay;
/* Continue a partial initialization */
- if (type == HUB_INIT2)
- goto init2;
- if (type == HUB_INIT3)
+ if (type == HUB_INIT2 || type == HUB_INIT3) {
+ device_lock(hub->intfdev);
+
+ /* Was the hub disconnected while we were waiting? */
+ if (hub->disconnected) {
+ device_unlock(hub->intfdev);
+ kref_put(&hub->kref, hub_release);
+ return;
+ }
+ if (type == HUB_INIT2)
+ goto init2;
goto init3;
+ }
+ kref_get(&hub->kref);
/* The superspeed hub except for root hub has to use Hub Depth
* value as an offset into the route string to locate the bits
@@ -1228,6 +1239,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
queue_delayed_work(system_power_efficient_wq,
&hub->init_work,
msecs_to_jiffies(delay));
+ device_unlock(hub->intfdev);
return; /* Continues at init3: below */
} else {
msleep(delay);
@@ -1249,6 +1261,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
/* Allow autosuspend if it was suppressed */
if (type <= HUB_INIT3)
usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
+
+ if (type == HUB_INIT2 || type == HUB_INIT3)
+ device_unlock(hub->intfdev);
+
+ kref_put(&hub->kref, hub_release);
}
/* Implement the continuations for the delays above */
This is a note to let you know that I have just added a patch titled USB: fix invalid memory access in hub_activate() to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt23. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ---8<------------------------------------------------------------ From 3367e6dc5e91f7bf8439ef2ddcb05d3a182df871 Mon Sep 17 00:00:00 2001 From: Alan Stern <stern@rowland.harvard.edu> Date: Wed, 16 Dec 2015 13:32:38 -0500 Subject: USB: fix invalid memory access in hub_activate() commit e50293ef9775c5f1cf3fcc093037dd6a8c5684ea upstream. Commit 8520f38099cc ("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: 8520f38099cc ("USB: change hub initialization sleeps to delayed_work") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ luis: backported to 3.16: - Added forward declaration of hub_release() which mainline had with commit 32a6958998c5 ("usb: hub: convert khubd into workqueue") ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/usb/core/hub.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-)