[2.28 COMMITTED] Fix stack overflow in tst-setcontext9 (bug 23717)

[Florian Weimer]

From: Andreas Schwab <schwab@suse.de>

The function f1a, executed on a stack of size 32k, allocates an object of
size 32k on the stack.  Make the stack variables static to reduce
excessive stack usage.

(cherry picked from commit f841c97e515a1673485a2b12b3c280073d737890)

2018-09-27  Andreas Schwab  <schwab@suse.de>

	[BZ #23717]
	* stdlib/tst-setcontext9.c (f1a): Make st2 static.
	(do_test): Make st1 static.

diff --git a/NEWS b/NEWS
index d1f1dd4b22..bc568bcec0 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,7 @@ The following bugs are resolved with this release:
   [23578] regex: Fix memory overread in re_compile_pattern
   [23606] Missing ENDBR32 in sysdeps/i386/start.S
   [23679] gethostid: Missing NULL check for gethostbyname_r result
+  [23717] Fix stack overflow in stdlib/tst-setcontext9
 
 
 Version 2.28
diff --git a/stdlib/tst-setcontext9.c b/stdlib/tst-setcontext9.c
index db8355766c..009928235d 100644
--- a/stdlib/tst-setcontext9.c
+++ b/stdlib/tst-setcontext9.c
@@ -58,7 +58,7 @@ f1b (void)
 static void
 f1a (void)
 {
-  char st2[32768];
+  static char st2[32768];
   puts ("start f1a");
   if (getcontext (&ctx[2]) != 0)
     {
@@ -93,7 +93,7 @@ f1a (void)
 static int
 do_test (void)
 {
-  char st1[32768];
+  static char st1[32768];
   puts ("making contexts");
   if (getcontext (&ctx[0]) != 0)
     {