[libusb] libusb submit_transfer seg fault

[Banerjee, T. S. (MU-Student) <ts...@ma...>]

Hi,
Trying again..

I am a newbie in linux so I'd really appreciate your help.
I am using libusb-1.0.9 which I compiled from source on a Debian 6.0.7 machine. To give you a better idea of the project, I am trying to hook up a Dreamplug using a Kinect so I need the libusb to interact with the Kinect device.

To do that, from my function I call :

dev->depth.pkt_size = DEPTH_PKTDSIZE;
dev->depth.synced = 0;
dev->depth.flag = 0x70;
dev->depth.valid_frames = 0;
dev->depth.stf = 0;

res = fnusb_start_iso(&dev->usb_cam, &dev->depth_isoc, depth_process, 0x82, DEPTH_NUM_XFERS, PKTS_PER_XFER, DEPTH_PKTBUF);

This in turn links to usb_libusb10.c


int fnusb_start_iso(fnusb_dev *dev, fnusb_isoc_stream *strm, fnusb_iso_cb cb, int ep, int xfers, int pkts, int len)
{
freenect_context *ctx = dev->parent->parent;
int ret, i;

strm->parent = dev;
strm->cb = cb;
strm->num_xfers = xfers;
strm->pkts = pkts;
strm->len = len;
strm->buffer = (uint8_t*)malloc(xfers * pkts * len);
strm->xfers = (struct libusb_transfer**)malloc(sizeof(struct libusb_transfer*) * xfers);
strm->dead = 0;
strm->dead_xfers = 0;

uint8_t *bufp = strm->buffer;

for (i=0; i<xfers; i++) {
printf("Creating EP %02x transfer #%d\n", ep, i);
strm->xfers[i] = libusb_alloc_transfer(pkts);

libusb_fill_iso_transfer(strm->xfers[i], dev->dev, ep, bufp, pkts * len, pkts, iso_callback, strm, 0);

libusb_set_iso_packet_lengths(strm->xfers[i], len);

ret = libusb_submit_transfer(strm->xfers[i]);
.
.
.
After linking this to the libusb-1.0.9 source code, it goes to io.c

 Unfortunately, there is a seg fault inside io.c at

struct libusb_context *ctx = TRANSFER_CTX(transfer);

The debug statements indicate that it reaches inside the function and then seg faults on this line.
I tried initializing the pointer to NULL and also have been playing around with the packet parameters in the hope that if there is a stack overflow, that should help. Any suggestions?


Thanks,
Tanvi