[Libusb-devel] [libusb] #88: [PATCH] Crash cancelling transfer of disconnected device

[libusb T. <tr...@li...>]

#88: [PATCH] Crash cancelling transfer of disconnected device
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 Reporter:  www.google.com/accounts/o8/id?id=aitoawmz93igogrpknbehv21jdxrf37ft8ksncg  |        Owner:     
     Type:  defect                                                                    |       Status:  new
Component:  libusb-1.0                                                                |     Keywords:     
   Blocks:                                                                            |   Blocked By:     
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 Reproduced this on OSX.  Haven't tried yet on Linux.

 I set up and submit a control transfer, but in the middle I disconnect the
 device.

 It crashes (with signal EXC_BAD_ACCESS) on line 1307 (in
 cancel_control_transfer of darwin_usb.c):

 {{{
 kresult = (*(dpriv->device))->USBDeviceAbortPipeZero (dpriv->device);
 }}}

 I think it's a race condition where dpriv->device is made NULL by whatever
 code detects that the device has disconnected.  A simple patch for this
 particular code path is:

 {{{
 if (!dpriv->device)
   return LIBUSB_ERROR_NO_DEVICE;

 kresult = (*(dpriv->device))->USBDeviceAbortPipeZero (dpriv->device);
 }}}

 There may be a more generic code path available (& more code paths where
 this needs to be done).

-- 
Ticket URL: <http://libusb.org/ticket/88>
libusb <http://libusb.org/>
C library for writing portable USB drivers in userspace