A Linux developer from Red Hat has accused a fellow kernel developer of his company violating the GPL. The developer is the sub-system maintainer for the in-kernel SCSI target support within the mainline Linux kernel and is also employed by Rising Tide Systems, the storage company with the alleged violation. It's alleged that the company took advantage of some GPL-licensed code in order to gain VMware vSphere 5 VAAI support for their unified storage operating system. He made these accusations public on the LKML after private emails were unsuccessful in resolving the situation.
The response from the in-kernel SCSI target maintainer is that there is no GPL violation because they wrote the original GPL code in question and have exclusive copyright ownership over the code with supposedly not having any GPL code from the community. The company had submitted the Linux SCSI target code to the kernel that they originally wrote themselves. For their storage OS they also are said to have their own proprietary version of the code-base. Basically, their response is they have a dual-licensed version of the code.
There was an additional follow-up, "We contributed our target to the Linux kernel in 2010, at which point we forked it into the upstream version and our commercial version. These target versions have been diverging over time, as we keep maintaining either one of them independently. For our commercial target core, we only use Linux kernel symbols that are not marked as GPL. In addition, we define the API between the target core and its backend drivers and between the target core and its fabric modules, we define the ABI between the target core and user space, and we have done so years before our code went upstream into the Linux kernel. We have been contributing substantially to the upstream target version to keep improving Linux. We have also been improving our commercial target version to afford the considerable effort and expense involved in our ongoing Linux contributions, and to compensate other top Linux kernel developers for their contributions to the upstream target version."
Various other Linux kernel developers have jumped in on the conversation from David Airlie to Alan Cox to Ted Ts'o with their opinions on GPL violations and derivative works of the Linux kernel. Even the legal firm representing the company in question has responded to the thread with their legal views on derivative works of the Linux kernel. Bradley Kuhn of the Software Freedom Conservancy has also shared his views on the matter.
The matter is still unfolding with new mailing list posts continuing whether there is a GPL violation occurring or not with the situation being convoluted since it involves an active kernel sub-system maintainer and code that was previously contributed by the company in question.