A uprobes addendum
Posted Jan 25, 2010 15:10 UTC (Mon) by drag
In reply to: A uprobes addendum
Parent article: A uprobes addendum
NVidia can get away with what it does - producing a binary module with
GPL wrapper - only because its code doesn't need to touch too much of the
kernel and doesn't need to modify core routines.
Nvidia can probably get away with what it does because the Nvidia kernel
module is not, as far as anybody can tell, derivative of the Linux kernel.
"Derivative" is a legal term defined in USA copyright law and it indicates
were your copyrights rights end when dealing with other parties. If you did
not make it and it is not a derivative then there is no way any of your
GPL'd software could have a effect on it.
Apparently Nvidia kernel module is mostly Windows driver shoehorned into
Linux via the "GPL Wrapper". This sort of thing is very gray
somebody could challenge it and get it decided in court, but no copyright
holder in the Linux kernel has decided to do that. This "grayness" is
built into the system.. legal stuff is not programming stuff. It is
designed to allow flexibility.
HOWEVER if you take Solaris Dtrace code and plunk it into the kernel, and
then ship it, then your creating a derivative product of both Solaris and
Linux. Therefore you will be forced to deal with licensing issues and need
to provide a license for your product that will incorporate the licenses of
both copyright holder's requirements.
The CDDL is incompatible with GLv2-only code due to the additional
restrictions that the CDDL places on code that the GPLv2 does not allow.
The CDDL restrictions are not bad, they have to do with patent stuff, but
they exist and are in conflict with the wording of the GPL license.
That is all there is to it. You could probably combine the two and get away
with it just fine, but it is not something that a company is going to base
their ability to legally ship Linux on and kernel programmers are going to
put a lot of effort into.
The CDDL was designed to do this on purpose* and it is there to allow Sun
to produce a competitive product to Linux. They need to create product
differentiation between Linux and Solaris and Dtrace/ZFS is just about the
only way they can do it.
* The CDDL is based on the Mozilla license. The Mozilla license is
noteworthy (in this discussion) _because_ it created licensing conflicts
with GPL software in the past. Which is why, of course, Mozilla has gone
out of their way and legally stated that the GPL is compatible by
dual/triple licensing their code. (Mozilla/GPL/LGPL)
Even if the Linux developers wanted to incorporate Dtrace they could not
legally do so until Sun creates a legal exception for them. And, no, a Sun
employee stating in a blog that they "as far as they know would not sue"-
type statement is not legally binding.
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