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usb/isp1760: Fix race condition memory leak

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This fixes a memory leak reported by Catalin Marinas:

schedule_ptds() is called from isp1760_irq() and removes the qh from the
controlqhs queue but ep->hcpriv still points to the qh and therefore it is not
freed.

Shortly after this, the isp1760_endpoint_disable() function sets ep->hcpriv to
NULL and calls schedule_ptds() but since the corresponding qh is no longer in
the queue, it is simply forgotten and reported by kmemleak.

With this patch, the qh is always freed at endpoint_disable, instead, and the
corresponding entry removed from the queue head list.

While I was at it, I also replaced the lines in isp1760_endpoint_disable()
that removed remaining qtds from the qh with a WARN_ON check for non-empty qh,
in line with earlier comments from Alan Stern (linux-usb list, 2011-07-20).

Signed-off-by: Arvid Brodin <arvid.brodin@enea.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Arvid Brodin 2011-11-23 18:13:02 +01:00 committed by Greg Kroah-Hartman
parent e08f6a2790
commit c64391f264
1 changed files with 12 additions and 18 deletions
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30
drivers/usb/host/isp1760-hcd.c
View File

@ -937,7 +937,6 @@ void schedule_ptds(struct usb_hcd *hcd)
struct isp1760_hcd *priv; struct isp1760_hcd *priv;
struct isp1760_qh *qh, *qh_next; struct isp1760_qh *qh, *qh_next;
struct list_head *ep_queue; struct list_head *ep_queue;
struct usb_host_endpoint *ep;
LIST_HEAD(urb_list); LIST_HEAD(urb_list);
struct urb_listitem *urb_listitem, *urb_listitem_next; struct urb_listitem *urb_listitem, *urb_listitem_next;
int i; int i;
@ -955,17 +954,9 @@ void schedule_ptds(struct usb_hcd *hcd)
for (i = 0; i < QH_END; i++) { for (i = 0; i < QH_END; i++) {
ep_queue = &priv->qh_list[i]; ep_queue = &priv->qh_list[i];
list_for_each_entry_safe(qh, qh_next, ep_queue, qh_list) { list_for_each_entry_safe(qh, qh_next, ep_queue, qh_list) {
ep = list_entry(qh->qtd_list.next, struct isp1760_qtd,
qtd_list)->urb->ep;
collect_qtds(hcd, qh, &urb_list); collect_qtds(hcd, qh, &urb_list);
if (list_empty(&qh->qtd_list)) { if (list_empty(&qh->qtd_list))
list_del(&qh->qh_list); list_del(&qh->qh_list);
if (ep->hcpriv == NULL) {
/* Endpoint has been disabled, so we
can free the associated queue head. */
qh_free(qh);
}
}
} }
} }
@ -1708,8 +1699,8 @@ static void isp1760_endpoint_disable(struct usb_hcd *hcd,
{ {
struct isp1760_hcd *priv = hcd_to_priv(hcd); struct isp1760_hcd *priv = hcd_to_priv(hcd);
unsigned long spinflags; unsigned long spinflags;
struct isp1760_qh *qh; struct isp1760_qh *qh, *qh_iter;
struct isp1760_qtd *qtd; int i;
spin_lock_irqsave(&priv->lock, spinflags); spin_lock_irqsave(&priv->lock, spinflags);
@ -1717,14 +1708,17 @@ static void isp1760_endpoint_disable(struct usb_hcd *hcd,
if (!qh) if (!qh)
goto out; goto out;
list_for_each_entry(qtd, &qh->qtd_list, qtd_list) WARN_ON(!list_empty(&qh->qtd_list));
if (qtd->status != QTD_RETIRE) {
dequeue_urb_from_qtd(hcd, qh, qtd);
qtd->urb->status = -ECONNRESET;
}
for (i = 0; i < QH_END; i++)
list_for_each_entry(qh_iter, &priv->qh_list[i], qh_list)
if (qh_iter == qh) {
list_del(&qh_iter->qh_list);
i = QH_END;
break;
}
qh_free(qh);
ep->hcpriv = NULL; ep->hcpriv = NULL;
/* Cannot free qh here since it will be parsed by schedule_ptds() */
schedule_ptds(hcd); schedule_ptds(hcd);