Mercurial > gnulib
view m4/isnan.m4 @ 37246:5cfb3a67238d
regex: avoid glibc deadlock during configure
glibc has a known bug where certain corruptions of the heap can
cause malloc to default to printing a debug message that includes
a backtrace, but the act of getting the backtrace uses dlopen
which in turn calls into malloc, causing a recursive lock ending
in deadlock. Thus, when configure is probing for a known glibc
heap corruption bug, the overall configure would hang.
The solution suggested by glibc developers is to force malloc
to quit printing debug messages, which avoids recursive malloc.
* m4/regex.m4 (gl_REGEX): Avoid recursive malloc deadlock when
glibc bug 15078 in turn triggers bug 16159.
Reported by Michal Privoznik.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Tue, 03 Dec 2013 10:34:13 -0700 |
parents | c741bc27922a |
children | 344018b6e5d7 |
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# isnan.m4 serial 5 dnl Copyright (C) 2007-2013 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_ISNAN], [ AC_REQUIRE([gl_MATH_H_DEFAULTS]) AC_REQUIRE([gl_FUNC_ISNANF]) AC_REQUIRE([gl_FUNC_ISNAND]) AC_REQUIRE([gl_FUNC_ISNANL]) # If we replaced any of the underlying isnan* functions, replace # the isnan macro; it undoubtedly suffers from the same flaws. AC_MSG_CHECKING([whether isnan macro works]) if test $gl_func_isnanf = yes \ && test $gl_func_isnand = yes \ && test $gl_func_isnanl = yes; then AC_MSG_RESULT([yes]) ISNAN_LIBM= dnl Append $ISNANF_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates. case " $ISNAN_LIBM " in *" $ISNANF_LIBM "*) ;; *) ISNAN_LIBM="$ISNAN_LIBM $ISNANF_LIBM" ;; esac dnl Append $ISNAND_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates. case " $ISNAN_LIBM " in *" $ISNAND_LIBM "*) ;; *) ISNAN_LIBM="$ISNAN_LIBM $ISNAND_LIBM" ;; esac dnl Append $ISNANL_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates. case " $ISNAN_LIBM " in *" $ISNANL_LIBM "*) ;; *) ISNAN_LIBM="$ISNAN_LIBM $ISNANL_LIBM" ;; esac else AC_MSG_RESULT([no]) dnl REPLACE_ISNAN=1 also makes sure the rpl_isnan[fdl] functions get built. REPLACE_ISNAN=1 ISNAN_LIBM= fi AC_SUBST([ISNAN_LIBM]) ])