usbip: Fix free of unallocated memory in vhci tx
iso_buffer should be set to NULL after use and free in the while loop.
In the case of isochronous URB in the while loop, iso_buffer is
allocated and after sending it to server, buffer is deallocated. And
then, if the next URB in the while loop is not a isochronous pipe,
iso_buffer still holds the previously deallocated buffer address and
kfree tries to free wrong buffer address.
Fixes: ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver")
Reported-by: kbuild test robot <firstname.lastname@example.org>
Reported-by: Julia Lawall <email@example.com>
Signed-off-by: Suwan Kim <firstname.lastname@example.org>
Reviewed-by: Julia Lawall <email@example.com>
Acked-by: Shuah Khan <firstname.lastname@example.org>
Signed-off-by: Greg Kroah-Hartman <email@example.com>