From a6632fee28d5c0befa192c92692e4204656a29a0 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 9 Mar 2021 11:22:59 -0800 Subject: Port alternate signal stack to upcoming glibc 2.34 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * src/sysdep.c (sigsegv_stack): Increase size to 64 KiB and align it to max_align_t. This copies from Gnulib’s c-stack.c, and works around a portability bug in draft glibc 2.34, which no longer defines SIGSTKSZ when _GNU_SOURCE is defined. (cherry picked from commit f97e07ea807cc6d38774a3888a15091b20645ac6) --- src/sysdep.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/sysdep.c b/src/sysdep.c index b2aecc0ddac..1f7f02cb003 100644 --- a/src/sysdep.c +++ b/src/sysdep.c @@ -1792,7 +1792,15 @@ handle_arith_signal (int sig) /* Alternate stack used by SIGSEGV handler below. */ -static unsigned char sigsegv_stack[SIGSTKSZ]; +/* Storage for the alternate signal stack. + 64 KiB is not too large for Emacs, and is large enough + for all known platforms. Smaller sizes may run into trouble. + For example, libsigsegv 2.6 through 2.8 have a bug where some + architectures use more than the Linux default of an 8 KiB alternate + stack when deciding if a fault was caused by stack overflow. */ +static max_align_t sigsegv_stack[(64 * 1024 + + sizeof (max_align_t) - 1) + / sizeof (max_align_t)]; /* Return true if SIGINFO indicates a stack overflow. */ -- cgit v1.2.1