On Thu, Apr 01, 2021 at 12:38:31AM +0200, Thomas Gleixner wrote: > On Wed, Mar 31 2021 at 14:54, Kees Cook wrote: > > On Wed, Mar 31, 2021 at 09:53:26AM +0200, Thomas Gleixner wrote: > >> On Tue, Mar 30 2021 at 13:57, Kees Cook wrote: > >> > +/* > >> > + * Do not use this anywhere else in the kernel. This is used here because > >> > + * it provides an arch-agnostic way to grow the stack with correct > >> > + * alignment. Also, since this use is being explicitly masked to a max of > >> > + * 10 bits, stack-clash style attacks are unlikely. For more details see > >> > + * "VLAs" in Documentation/process/deprecated.rst > >> > + * The asm statement is designed to convince the compiler to keep the > >> > + * allocation around even after "ptr" goes out of scope. > >> > >> Nit. That explanation of "ptr" might be better placed right at the > >> add_random...() macro. > > > > Ah, yes! Fixed in v9. > > Hmm, looking at V9 the "ptr" thing got lost .... I put the comment inline in the macro directly above the asm(). > > Do you want to take this via -tip (and leave off the arm64 patch until > > it is acked), or would you rather it go via arm64? (I've sent v9 now...) > > Either way is fine. Since the arm64 folks have been a bit busy, can you just put this in -tip and leave off the arm64 patch for now? Thanks! -- Kees Cook
