On 11/28/2013 07:34 AM, Eric Blake wrote: [back from holidays, so reviving this thread]
>> Michal, since you have the environment to test this, can you rerun:
>>
>> ./configure MALLOC_CHECK_=2
>>
>> and see if the hang goes away? If so, then I know how to patch gnulib
>> to ensure that this particular environment variable is always set for
>> each conftest that tries to tickle a known glibc memory corruption bug.
Michal complained that setting MALLOC_CHECK_ for the entire configure
slowed things down.
>
> On IRC, Michal confirmed that this hack patch helped avoid a conftest hang:
>
> diff --git i/m4/regex.m4 w/m4/regex.m4
> index 424ae33..b0eed19 100644
> --- i/m4/regex.m4
> +++ w/m4/regex.m4
> -41,6 +41,15 @@ AC_DEFUN([gl_REGEX],
> # include <unistd.h>
> # include <signal.h>
> #endif
> +#ifdef __linux__
> +#include <execinfo.h>
> +static void __attribute__ ((constructor))
> +init_backtrace()
> +{
> + void *bt[10];
> + backtrace (bt, 10);
> +}
> +#endif
> ]],
> [[int result = 0;
> static struct re_pattern_buffer regex;
He also said this approach worked:
diff --git i/m4/regex.m4 w/m4/regex.m4
index 424ae33..0089c08 100644
--- i/m4/regex.m4
+++ w/m4/regex.m4
@@ -1,4 +1,4 @@
-# serial 64
+# serial 65
# Copyright (C) 1996-2001, 2003-2013 Free Software Foundation, Inc.
#
@@ -28,6 +28,7 @@ AC_DEFUN([gl_REGEX],
# If cross compiling, assume the test would fail and use the included
# regex.c.
AC_CHECK_DECLS_ONCE([alarm])
+ AC_CHECK_HEADERS_ONCE([malloc.h])
AC_CACHE_CHECK([for working re_compile_pattern],
[gl_cv_func_re_compile_pattern_working],
[AC_RUN_IFELSE(
@@ -41,6 +42,9 @@ AC_DEFUN([gl_REGEX],
# include <unistd.h>
# include <signal.h>
#endif
+ #if HAVE_MALLOC_H
+ # include <malloc.h>
+ #endif
]],
[[int result = 0;
static struct re_pattern_buffer regex;
@@ -49,11 +53,17 @@ AC_DEFUN([gl_REGEX],
const char *s;
struct re_registers regs;
+ /* Some builds of glibc go into an infinite loop on this
+ test. Use alarm to force death, and mallopt to avoid
+ malloc recursion in diagnosing the corrupted heap. */
#if HAVE_DECL_ALARM
- /* Some builds of glibc go into an infinite loop on this
test. */
signal (SIGALRM, SIG_DFL);
alarm (2);
#endif
+#ifdef M_CHECK_ACTION
+ mallopt(M_CHECK_ACTION, 2);
+#endif
+
if (setlocale (LC_ALL, "en_US.UTF-8"))
{
{
Any preferences on which one I should use in gnulib?
>
> But then he reported that the check for a working sleep() hung, which
> makes me wonder if SIGALRM/alarm() semantics are broken on his system.
No idea what was happening here, but it's a separate issue to debug if
it is still happening.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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