Christoph Hellwig wrote: > we've had a bug in our resolution of _GPL modules since day one, that > is a module can claim to be GPL licensed and use _GPL exports, while > it also depends on symbols from non-GPL modules. This is used as a > circumvention of the _GPL exports by using a small shim module using > the _GPL exports and the other functionality.
This looks great. You might also consider doing the reverse: if a module imports any EXPORT_SYMBOL_GPL symbols, any symbols that module in turn exports shouldn't be importable by any module that doesn't explicitly claim to be GPL-compatible. Effectively, if a module imports any EXPORT_SYMBOL_GPL symbols, all of its exported symbols would then be treated as EXPORT_SYMBOL_GPL. This would catch the case of attempting to "wrap" EXPORT_SYMBOL_GPL symbols in the other direction, by re-exporting the same or similar functions to another module. (This would help catch mistakes, not just intentional malice.) - Josh Triplett
