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? In practice software just assumes SIGSTKSZ and then ignores the problem until / unless an actual stack overflow is seen. There's probably a lot of software out there whose stack is theoretically too small even without AVX-512 etc. in the mix, especially when considering the possibility of nested signals... Cheers ---Dave
