target/linux/brcm2708/patches-3.10/0082-dwc_otg-prevent-OOPSes-during-device-disconnects.patch

   1 From dc570a70493daf0ec548ff57f1a1a9fb31caccb7 Mon Sep 17 00:00:00 2001
   2 From: P33M <P33M@github.com>
   3 Date: Thu, 18 Jul 2013 17:07:26 +0100
   4 Subject: [PATCH 082/174] dwc_otg: prevent OOPSes during device disconnects
   5
   6 The dwc_otg_urb_enqueue function is thread-unsafe. In particular the
   7 access of urb->hcpriv, usb_hcd_link_urb_to_ep, dwc_otg_urb->qtd and
   8 friends does not occur within a critical section and so if a device
   9 was unplugged during activity there was a high chance that the
  10 usbcore hub_thread would try to disable the endpoint with partially-
  11 formed entries in the URB queue. This would result in BUG() or null
  12 pointer dereferences.
  13
  14 Fix so that access of urb->hcpriv, enqueuing to the hardware and
  15 adding to usbcore endpoint URB lists is contained within a single
  16 critical section.
  17 ---
  18  drivers/usb/host/dwc_otg/dwc_otg_hcd.c       |  3 ---
  19  drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c | 14 +++++---------
  20  drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c |  6 +-----
  21  3 files changed, 6 insertions(+), 17 deletions(-)
  22
  23 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
  24 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
  25 @@ -464,7 +464,6 @@ int dwc_otg_hcd_urb_enqueue(dwc_otg_hcd_
  26                             dwc_otg_hcd_urb_t * dwc_otg_urb, void **ep_handle,
  27                             int atomic_alloc)
  28  {
  29 -       dwc_irqflags_t flags;
  30         int retval = 0;
  31         uint8_t needs_scheduling = 0;
  32         dwc_otg_transaction_type_e tr_type;
  33 @@ -515,12 +514,10 @@ int dwc_otg_hcd_urb_enqueue(dwc_otg_hcd_
  34         }
  35
  36         if(needs_scheduling) {
  37 -               DWC_SPINLOCK_IRQSAVE(hcd->lock, &flags);
  38                 tr_type = dwc_otg_hcd_select_transactions(hcd);
  39                 if (tr_type != DWC_OTG_TRANSACTION_NONE) {
  40                         dwc_otg_hcd_queue_transactions(hcd, tr_type);
  41                 }
  42 -               DWC_SPINUNLOCK_IRQRESTORE(hcd->lock, flags);
  43         }
  44         return retval;
  45  }
  46 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c
  47 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c
  48 @@ -679,9 +679,7 @@ static int dwc_otg_urb_enqueue(struct us
  49  #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28)
  50         struct usb_host_endpoint *ep = urb->ep;
  51  #endif
  52 -#if USB_URB_EP_LINKING
  53         dwc_irqflags_t irqflags;
  54 -#endif
  55          void **ref_ep_hcpriv = &ep->hcpriv;
  56         dwc_otg_hcd_t *dwc_otg_hcd = hcd_to_dwc_otg_hcd(hcd);
  57         dwc_otg_hcd_urb_t *dwc_otg_urb;
  58 @@ -733,7 +731,6 @@ static int dwc_otg_urb_enqueue(struct us
  59         if(dwc_otg_urb == NULL)
  60                 return -ENOMEM;
  61
  62 -       urb->hcpriv = dwc_otg_urb;
  63         if (!dwc_otg_urb && urb->number_of_packets)
  64                 return -ENOMEM;
  65
  66 @@ -775,10 +772,10 @@ static int dwc_otg_urb_enqueue(struct us
  67                                                     iso_frame_desc[i].length);
  68         }
  69
  70 -#if USB_URB_EP_LINKING
  71         DWC_SPINLOCK_IRQSAVE(dwc_otg_hcd->lock, &irqflags);
  72 +       urb->hcpriv = dwc_otg_urb;
  73 +#if USB_URB_EP_LINKING
  74         retval = usb_hcd_link_urb_to_ep(hcd, urb);
  75 -       DWC_SPINUNLOCK_IRQRESTORE(dwc_otg_hcd->lock, irqflags);
  76         if (0 == retval)
  77  #endif
  78         {
  79 @@ -794,17 +791,16 @@ static int dwc_otg_urb_enqueue(struct us
  80                                                 urb);
  81                         }
  82                 } else {
  83 -#if USB_URB_EP_LINKING
  84 -                       dwc_irqflags_t irqflags;
  85                         DWC_DEBUGPL(DBG_HCD, "DWC OTG dwc_otg_hcd_urb_enqueue failed rc %d\n", retval);
  86 -                       DWC_SPINLOCK_IRQSAVE(dwc_otg_hcd->lock, &irqflags);
  87 +#if USB_URB_EP_LINKING
  88                         usb_hcd_unlink_urb_from_ep(hcd, urb);
  89 -                       DWC_SPINUNLOCK_IRQRESTORE(dwc_otg_hcd->lock, irqflags);
  90  #endif
  91 +                       urb->hcpriv = NULL;
  92                         if (retval == -DWC_E_NO_DEVICE)
  93                                 retval = -ENODEV;
  94                 }
  95         }
  96 +       DWC_SPINUNLOCK_IRQRESTORE(dwc_otg_hcd->lock, irqflags);
  97         return retval;
  98  }
  99
 100 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c
 101 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c
 102 @@ -919,6 +919,7 @@ void dwc_otg_hcd_qtd_init(dwc_otg_qtd_t
 103   * QH to place the QTD into.  If it does not find a QH, then it will create a
 104   * new QH. If the QH to which the QTD is added is not currently scheduled, it
 105   * is placed into the proper schedule based on its EP type.
 106 + * HCD lock must be held and interrupts must be disabled on entry
 107   *
 108   * @param[in] qtd The QTD to add
 109   * @param[in] hcd The DWC HCD structure
 110 @@ -931,8 +932,6 @@ int dwc_otg_hcd_qtd_add(dwc_otg_qtd_t *
 111                         dwc_otg_hcd_t * hcd, dwc_otg_qh_t ** qh, int atomic_alloc)
 112  {
 113         int retval = 0;
 114 -       dwc_irqflags_t flags;
 115 -
 116         dwc_otg_hcd_urb_t *urb = qtd->urb;
 117
 118         /*
 119 @@ -946,15 +945,12 @@ int dwc_otg_hcd_qtd_add(dwc_otg_qtd_t *
 120                         goto done;
 121                 }
 122         }
 123 -       DWC_SPINLOCK_IRQSAVE(hcd->lock, &flags);
 124         retval = dwc_otg_hcd_qh_add(hcd, *qh);
 125         if (retval == 0) {
 126                 DWC_CIRCLEQ_INSERT_TAIL(&((*qh)->qtd_list), qtd,
 127                                         qtd_list_entry);
 128                 qtd->qh = *qh;
 129         }
 130 -       DWC_SPINUNLOCK_IRQRESTORE(hcd->lock, flags);
 131 -
 132  done:
 133
 134         return retval;