| Andrew Geissler | f103a7f | 2021-05-07 16:09:40 -0500 | [diff] [blame] | 1 | From f97e07ea807cc6d38774a3888a15091b20645ac6 Mon Sep 17 00:00:00 2001 |
| 2 | From: Paul Eggert <eggert@cs.ucla.edu> |
| 3 | Date: Tue, 9 Mar 2021 11:22:59 -0800 |
| 4 | Subject: [PATCH] Port alternate signal stack to upcoming glibc 2.34 |
| 5 | MIME-Version: 1.0 |
| 6 | Content-Type: text/plain; charset=UTF-8 |
| 7 | Content-Transfer-Encoding: 8bit |
| 8 | |
| 9 | * src/sysdep.c (sigsegv_stack): Increase size to 64 KiB and align |
| 10 | it to max_align_t. This copies from Gnulib’s c-stack.c, and works |
| 11 | around a portability bug in draft glibc 2.34, which no longer |
| 12 | defines SIGSTKSZ when _GNU_SOURCE is defined. |
| 13 | --- |
| 14 | src/sysdep.c | 10 +++++++++- |
| 15 | 1 file changed, 9 insertions(+), 1 deletion(-) |
| 16 | |
| 17 | diff --git a/src/sysdep.c b/src/sysdep.c |
| 18 | index 941b4e2fa2..24d8832b2f 100644 |
| 19 | --- a/src/sysdep.c |
| 20 | +++ b/src/sysdep.c |
| 21 | @@ -1785,7 +1785,15 @@ handle_arith_signal (int sig) |
| 22 | |
| 23 | /* Alternate stack used by SIGSEGV handler below. */ |
| 24 | |
| 25 | -static unsigned char sigsegv_stack[SIGSTKSZ]; |
| 26 | +/* Storage for the alternate signal stack. |
| 27 | + 64 KiB is not too large for Emacs, and is large enough |
| 28 | + for all known platforms. Smaller sizes may run into trouble. |
| 29 | + For example, libsigsegv 2.6 through 2.8 have a bug where some |
| 30 | + architectures use more than the Linux default of an 8 KiB alternate |
| 31 | + stack when deciding if a fault was caused by stack overflow. */ |
| 32 | +static max_align_t sigsegv_stack[(64 * 1024 |
| 33 | + + sizeof (max_align_t) - 1) |
| 34 | + / sizeof (max_align_t)]; |
| 35 | |
| 36 | |
| 37 | /* Return true if SIGINFO indicates a stack overflow. */ |
| 38 | -- |
| 39 | 2.29.2 |
| 40 | |