On Mon, Mar 15, 2021 at 11:52:14PM -0700, Chang S. Bae wrote: > @@ -272,7 +275,8 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, > * If we are on the alternate signal stack and would overflow it, don't. > * Return an always-bogus address instead so we will die with SIGSEGV. > */ > - if (onsigstack && !likely(on_sig_stack(sp))) > + if (onsigstack && unlikely(sp <= current->sas_ss_sp || > + sp - current->sas_ss_sp > current->sas_ss_size)) > return (void __user *)-1L; So clearly I'm missing something because trying to trigger the test case in the bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=153531 on current tip/master doesn't work. Runs with MY_MINSIGSTKSZ under 2048 fail with: tst-minsigstksz-2: sigaltstack: Cannot allocate memory and above 2048 don't overwrite bytes below the stack. So something else is missing. How did you test this patch? Thx. -- Regards/Gruss, Boris. SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg