| From f97e07ea807cc6d38774a3888a15091b20645ac6 Mon Sep 17 00:00:00 2001 |
| From: Paul Eggert <eggert@cs.ucla.edu> |
| Date: Tue, 9 Mar 2021 11:22:59 -0800 |
| Subject: [PATCH] Port alternate signal stack to upcoming glibc 2.34 |
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| |
| * 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. |
| --- |
| src/sysdep.c | 10 +++++++++- |
| 1 file changed, 9 insertions(+), 1 deletion(-) |
| |
| diff --git a/src/sysdep.c b/src/sysdep.c |
| index 941b4e2fa2..24d8832b2f 100644 |
| --- a/src/sysdep.c |
| +++ b/src/sysdep.c |
| @@ -1785,7 +1785,15 @@ 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. */ |
| -- |
| 2.29.2 |
| |