(+Luis for the usermode helper discussion) On Fri, Jul 11, 2025 at 04:44:23PM +0100, Al Viro wrote: > On Fri, Jul 11, 2025 at 12:35:59PM +0200, Thomas Weißschuh wrote: > > Hi Kees, Al, Christian and Honza, > > > > On Thu, Jun 26, 2025 at 08:10:14AM +0200, Thomas Weißschuh wrote: > > > The KUnit UAPI infrastructure starts userspace processes. > > > As it should be able to be built as a module, export the necessary symbols. > > What's wrong with kernel/umh.c? It gets neutered by CONFIG_STATIC_USERMODEHELPER_PATH. That could be worked around be overriding sub_info->path, but it would be a hack. It does not allow to implement a custom wait routine to forward the process output to KUnit as implemented in kunit_uapi_forward_to_printk() [0]. That may be solved by adding another thread, but that would also be hacky. It would probably be possible to extend kernel/umh.c for my usecase but I didn't want bloat the core kernel code for my test-only functionality. > > could you take a look at these new symbol exports? > > > > +EXPORT_SYMBOL_GPL_FOR_MODULES(put_filesystem, "kunit-uapi"); > > What's that one for??? What are you referring to? The macro EXPORT_SYMBOL_GPL_FOR_MODULES() will only export the symbol for one specific module. Personally I'm also fine with EXPORT_SYMBOL_GPL(). "kunit-uapi" is a new module I am implementing in this patchset. It allows to run userspace executables as part of KUnit. Some more information in the cover-letter [1] of the series and the code using these symbols[0]. Both should also be in your inbox. There is also an article on LWN [2]. [0] https://lore.kernel.org/lkml/20250626-kunit-kselftests-v4-12-48760534fef5@xxxxxxxxxxxxx/ [1] https://lore.kernel.org/lkml/20250626-kunit-kselftests-v4-0-48760534fef5@xxxxxxxxxxxxx/ [2] https://lwn.net/SubscriberLink/1029077/fa55c3b2d238a6bb/ Thomas
