From: Eric Blake <eblake@redhat.com>
Date: Thu, 21 Oct 2010 16:29:13 +0000 (-0600)
Subject: c-stack: work around libsigsegv 2.8 bug
X-Git-Tag: v0.1~3669
X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=b86f488e783121f54dbd44e17741fa3b29e9be9b;p=gnulib.git

c-stack: work around libsigsegv 2.8 bug

* lib/c-stack.c (SIGSTKSZ): Increase size to avoid alternate stack
overflow on at least PowerPC64.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

diff --git a/ChangeLog b/ChangeLog
index 30d89ea2a..a265b14bd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-10-21  Eric Blake  <eblake@redhat.com>
+
+	c-stack: work around libsigsegv 2.8 bug
+	* lib/c-stack.c (SIGSTKSZ): Increase size to avoid alternate stack
+	overflow on at least PowerPC64.
+
 2010-10-17  Bruno Haible  <bruno@clisp.org>
 
 	userspec: Drop redundant file.
diff --git a/lib/c-stack.c b/lib/c-stack.c
index 46575489d..0cf6b052d 100644
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -53,6 +53,12 @@ typedef struct sigaltstack stack_t;
 #endif
 #ifndef SIGSTKSZ
 # define SIGSTKSZ 16384
+#elif HAVE_LIBSIGSEGV && SIGSTKSZ < 16384
+/* libsigsegv 2.6 through 2.8 have a bug where some architectures use
+   more than the Linux default of an 8k alternate stack when deciding
+   if a fault was caused by stack overflow.  */
+# undef SIGSTKSZ
+# define SIGSTKSZ 16384
 #endif
 
 #include <stdlib.h>