An EFAULT error indicates we've have bad pointers and are writing / reading
random memory at that point all bets are off. If you can show me a real-world
example where we get another error then EFAULT and go into an infinite loop,
then I'm interested in fixing that. For the EFAULT problem you
miguelfreitas, please stop trying to somehow propagate the EFAULT and recover
from it. Something is causing bad pointers and/or memory corruption, once that
happens any predictable behavior is off the table.
I will only accept a patch for this if it turns out the bad pointers are caused
by a
If an EFAULT return from the kernel results in an infinite loop in
libusb(x):
It's not a matter of _recovering_ from the EFAULT. It's a matter of
whether libusb(x) should propagate it to the caller or not.
There is simply _no_ excuse not to propagate it.
Sarcasm on
Should we tell the kernel
I chose not to use memmove but rather read and write all buffer bytes in a loop
(not sure if memmove would optimize src==dst case). I could successfully
trigger the EFAULT and it did not cause any segfault.
patch (just for reference):
https://gist.github.com/miguelfreitas/8298825
besides i
@jwrdegoede I have read the processcompl() you mention and i agree the only
failure case is when one of the put_user or copy_to_user fails. -EFAULT is the
only error code used there.
Another raw guess: is it possible that data was corrupted during USB transfer
(this actually happens here due
@jwrdegoede here is what happens with current master:
```
libusbx: error [reap_for_handle] reap failed error -1 errno=14
libusbx: error [handle_events] backend handle_events failed with error -1
libusbx: error [sync_transfer_wait_for_completion] libusb_handle_events failed:
LIBUSB_ERROR_IO,
@jwrdegoede you are right about the previous patch being incorrect as you
pointed here:
http://sourceforge.net/mailarchive/message.php?msg_id=31068411
I have just tried exiting the while when libusb_cancel_transfer() != 0. As you
predicted, we can't use libusb_free_transfer() because it will
sigh. listen the EFAULT error is being thrown by this bit of code inside
libusb:
static int reap_for_handle(struct libusb_device_handle *handle)
{
struct usbfs_urb *urb;
int r = ioctl(hpriv-fd, IOCTL_USBFS_REAPURBNDELAY, urb);
if (r 0) {
Notice how the only address
