On Sat, Jun 08, 2024 at 04:44:16PM +0800, David Gow wrote: > On Mon, 20 May 2024 at 03:12, Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > For tests that need to allocate using vm_mmap() (e.g. usercopy and > > execve), provide the interface to have the allocation tracked by KUnit > > itself. This requires bringing up a placeholder userspace mm. > > > > This combines my earlier attempt at this with Mark Rutland's version[1]. > > > > Link: https://lore.kernel.org/lkml/20230321122514.1743889-2-mark.rutland@xxxxxxx/ [1] > > Co-developed-by: Mark Rutland <mark.rutland@xxxxxxx> > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > --- > > Thanks very much for this! > > A few high-level thoughts: > - Do we want to move this into a separate file? test.{c,h} is already > getting pretty big, and this would probably fit more comfortably with > some of the resource-management bits, which are in their own files. > Not every test will need mm support. I'm happy to do that -- I was just following where kunit_kmalloc() was defined. I'll create a new file for it. > - It'd be nice for there to be a way to explicitly teardown/reset > this: I agree that this is made more awkward by KUnit cleanup normally > running on a different thread, but I could definitely see why a test > might want to unset/reset this, and it would be more consistent with > other resources. Yeah, it's weird, but it's naturally managed? > Otherwise, I have a few small questions below, but nothing essential. > There are a couple of test failures/hangs for the usercopy test (on > i386 and m68k), which may have origins here: I've mentioned them > there. I'll look into this. I must have some 64/32 oversight... > Reviewed-by: David Gow <davidgow@xxxxxxxxxx> Thanks! > > +/* > > + * Arbitrarily chosen user address for the base allocation. > > + */ > > +#define UBUF_ADDR_BASE SZ_2M > > Are there any circumstances where we'd want a _different_ base address > here? Could it conflict with something / could tests require something > different? > > I suspect it's fine to leave it like this until such a case actually shows up. Yeah, it shouldn't be important, and as Mark has pointed out, it might not be needed at all. I'll see what I can do. > > + vres = kunit_alloc_resource(test, > > + kunit_vm_mmap_init, > > + kunit_vm_mmap_free, > > + GFP_KERNEL, > > + ¶ms); > > It could be easier to use kunit_add_action() here, rather than > kunit_alloc_resource(), as you wouldn't need the params struct to pass > things through. > > The advantage to keeping the separate resource is that we can more > easily look it up later if we, for example, wanted to be able to make > it current on other threads (is that something we'd ever want to do?). I like having it follow the pattern of the other resource allocators, but if there's not a strong reason to switch, I'll leave it as-is. -- Kees Cook
