On Mon, Aug 04, 2014 at 01:19:59PM +0100, Matt Fleming wrote: > On Fri, 01 Aug, at 09:11:54AM, Josh Triplett wrote: > > > > The original bug report was about an allocation failure for a fairly > > reasonable BGRT size. We can certainly prohibit absurdly huge ones (for > > instance, bigger than the maximum likely screen resolution times 4 bytes > > per pixel), but allocation failures may well occur for smaller sizes, > > and I don't think we want to spew a massive warning for that either. > > Oh, dammit, that's my bad. I misread the allocation size and thought it > was huge, but now realise it was only 6MB or so. Sorry Josh. > > I was worried that this was the first reported instance of a BGRT > claiming to be valid but with a bogusly large image size. I've never > been so happy to be wrong. :) > However, the fact that the allocation failed is worth investigating - > this machine appears to have GBs of ram. Perhaps we should switch to > requesting pages directly instead of relying on kmalloc()? > > I appreciate that the BGRT code isn't mission critical or anything like > that, and that failing the alloc isn't the end of the world, but if we > have code in the kernel it should really be as robust as possible. I > don't think trying to kmalloc() ~6MB can claim to be robust. vmalloc or flex_array could potentially help here. However, I'd suggest we go ahead and merge this patch to improve the existing error handling before doing a more extensive rewrite to use one of those. Would anything go horrifically wrong if this allocation used vmalloc? We really don't care deeply about the performance of this memory; it just needs a single copy in and a small number of copies out in the lifetime of a system. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
