On Tue, Oct 06, 2020 at 11:30:42AM -0700, Dave Hansen wrote: > On 10/6/20 10:00 AM, Dave Martin wrote: > > On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: > >> On 10/6/20 8:25 AM, Dave Martin wrote: > >>> Or are people reporting real stack overruns on x86 today? > >> We have real overruns. We have ~2800 bytes of XSAVE (regisiter) state > >> mostly from AVX-512, and a 2048 byte MINSIGSTKSZ. > > Right. Out of interest, do you believe that's a direct consequence of > > the larger kernel-generated signal frame, or does the expansion of > > userspace stack frames play a role too? > > The kernel-generated signal frame is entirely responsible for the ~2800 > bytes that I'm talking about. > > I'm sure there are some systems where userspace plays a role, but those > are much less of a worry at the moment, since the kernel-induced > overflows mean an instant crash that userspace has no recourse for. Ack, that sounds pretty convincing. Cheers ---Dave
