diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 10762ee14ccb..0f3b6eed13f7 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -2047,7 +2047,6 @@ ACLOCAL_AMFLAGS = -I ../config
 aclocal_m4_deps = \
 	configure.ac \
 	acx_configure_dir.m4 \
-	libmcheck.m4 \
 	transform.m4 \
 	../bfd/bfd.m4 \
 	../config/acinclude.m4 \
diff --git a/gdb/acinclude.m4 b/gdb/acinclude.m4
index b32dcf58c253..6e81aaed3bf4 100644
--- a/gdb/acinclude.m4
+++ b/gdb/acinclude.m4
@@ -6,9 +6,6 @@ dnl major rewriting for Tcl 7.5 by Don Libes <libes@nist.gov>
 
 sinclude(acx_configure_dir.m4)
 
-# This gets GDB_AC_LIBMCHECK.
-sinclude(libmcheck.m4)
-
 # This gets GDB_AC_TRANSFORM.
 sinclude(transform.m4)
 
diff --git a/gdb/config.in b/gdb/config.in
index 57ca593b9a8c..239ed361438e 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -246,9 +246,6 @@
 /* Define to 1 if you have the `m' library (-lm). */
 #undef HAVE_LIBM
 
-/* Define to 1 if you have the `mcheck' library (-lmcheck). */
-#undef HAVE_LIBMCHECK
-
 /* Define if you have the mpfr library. */
 #undef HAVE_LIBMPFR
 
diff --git a/gdb/configure b/gdb/configure
index f722d8032e1d..03645e1bad96 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -884,7 +884,6 @@ with_libmpfr_prefix
 with_python
 with_guile
 enable_source_highlight
-enable_libmcheck
 with_intel_pt
 with_libipt_prefix
 with_included_regex
@@ -1561,7 +1560,6 @@ if test -n "$ac_init_help"; then
   --enable-codesign=CERT  sign gdb with 'codesign -s CERT'
   --enable-source-highlight
                           enable source-highlight for source listings
-  --enable-libmcheck      Try linking with -lmcheck if available
   --enable-werror         treat compile warnings as errors
   --enable-build-warnings enable build-time compiler warnings if gcc is used
   --enable-gdb-build-warnings
@@ -11820,85 +11818,6 @@ fi
 
 
 
-# --------------------- #
-# Check for libmcheck.  #
-# --------------------- #
-
-# Enable -lmcheck by default (it provides cheap-enough memory mangling),
-# but turn it off if Python is enabled with threads, since -lmcheck is
-# not thread safe (http://sourceware.org/bugzilla/show_bug.cgi?id=9939),
-# and for releases.
-if test \( "${have_libpython}" = "no" -o "${python_has_threads}" = "no" \) \
-   && $development; then
-  libmcheck_default=yes
-else
-  libmcheck_default=no
-fi
-
-  # Check whether --enable-libmcheck was given.
-if test "${enable_libmcheck+set}" = set; then :
-  enableval=$enable_libmcheck; case "${enableval}" in
-      yes | y) ENABLE_LIBMCHECK="yes" ;;
-      no | n)  ENABLE_LIBMCHECK="no" ;;
-      *) as_fn_error $? "bad value ${enableval} for --enable-libmcheck" "$LINENO" 5 ;;
-    esac
-fi
-
-
-  if test -z "${ENABLE_LIBMCHECK}"; then
-    ENABLE_LIBMCHECK=${libmcheck_default}
-  fi
-
-  if test "$ENABLE_LIBMCHECK" = "yes" ; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for main in -lmcheck" >&5
-$as_echo_n "checking for main in -lmcheck... " >&6; }
-if ${ac_cv_lib_mcheck_main+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_check_lib_save_LIBS=$LIBS
-LIBS="-lmcheck  $LIBS"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-
-int
-main ()
-{
-return main ();
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_mcheck_main=yes
-else
-  ac_cv_lib_mcheck_main=no
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
-LIBS=$ac_check_lib_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_mcheck_main" >&5
-$as_echo "$ac_cv_lib_mcheck_main" >&6; }
-if test "x$ac_cv_lib_mcheck_main" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_LIBMCHECK 1
-_ACEOF
-
-  LIBS="-lmcheck $LIBS"
-
-fi
-
-  fi
-
-
-if test "$ENABLE_LIBMCHECK" = "yes" \
-	-a "${have_libpython}" != "no" \
-	-a "${python_has_threads}" = "yes" ; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: --enable-libmcheck may lead to spurious crashes if threads are used in python" >&5
-$as_echo "$as_me: WARNING: --enable-libmcheck may lead to spurious crashes if threads are used in python" >&2;}
-fi
-
 
 # Check whether --with-intel_pt was given.
 if test "${with_intel_pt+set}" = set; then :
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 4062d33f3e6e..bee923113b63 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1261,28 +1261,6 @@ fi
 AC_SUBST(SRCHIGH_LIBS)
 AC_SUBST(SRCHIGH_CFLAGS)
 
-# --------------------- #
-# Check for libmcheck.  #
-# --------------------- #
-
-# Enable -lmcheck by default (it provides cheap-enough memory mangling),
-# but turn it off if Python is enabled with threads, since -lmcheck is
-# not thread safe (http://sourceware.org/bugzilla/show_bug.cgi?id=9939),
-# and for releases.
-if test \( "${have_libpython}" = "no" -o "${python_has_threads}" = "no" \) \
-   && $development; then
-  libmcheck_default=yes
-else
-  libmcheck_default=no
-fi
-GDB_AC_LIBMCHECK(${libmcheck_default})
-
-if test "$ENABLE_LIBMCHECK" = "yes" \
-	-a "${have_libpython}" != "no" \
-	-a "${python_has_threads}" = "yes" ; then
-  AC_MSG_WARN(--enable-libmcheck may lead to spurious crashes if threads are used in python)
-fi
-
 AC_ARG_WITH(intel_pt,
   AS_HELP_STRING([--with-intel-pt], [include Intel Processor Trace support (auto/yes/no)]),
   [], [with_intel_pt=auto])
diff --git a/gdb/gdbserver/acinclude.m4 b/gdb/gdbserver/acinclude.m4
index 96ded3d7d390..3887b165c66c 100644
--- a/gdb/gdbserver/acinclude.m4
+++ b/gdb/gdbserver/acinclude.m4
@@ -3,9 +3,6 @@ sinclude(../../bfd/bfd.m4)
 
 sinclude(../acx_configure_dir.m4)
 
-# This gets GDB_AC_LIBMCHECK.
-sinclude(../libmcheck.m4)
-
 # This gets AM_GDB_WARNINGS.
 sinclude(../warning.m4)
 
diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in
index 05537df81e37..3991964f9bd5 100644
--- a/gdb/gdbserver/config.in
+++ b/gdb/gdbserver/config.in
@@ -123,9 +123,6 @@
 /* Define to 1 if you have the `dl' library (-ldl). */
 #undef HAVE_LIBDL
 
-/* Define to 1 if you have the `mcheck' library (-lmcheck). */
-#undef HAVE_LIBMCHECK
-
 /* Define if the target supports branch tracing. */
 #undef HAVE_LINUX_BTRACE
 
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index 0c04fcc8ae6a..7e5be51cb281 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -721,7 +721,6 @@ ac_user_opts='
 enable_option_checking
 enable_maintainer_mode
 enable_largefile
-enable_libmcheck
 enable_unit_tests
 with_ust
 with_ust_include
@@ -1367,7 +1366,6 @@ if test -n "$ac_init_help"; then
                           enable make rules and dependencies not useful (and
                           sometimes confusing) to the casual installer
   --disable-largefile     omit support for large files
-  --enable-libmcheck      Try linking with -lmcheck if available
   --enable-unit-tests     Enable the inclusion of unit tests when compiling
                           GDB
   --enable-werror         treat compile warnings as errors
@@ -1756,52 +1754,6 @@ $as_echo "$ac_res" >&6; }
 
 } # ac_fn_c_check_header_compile
 
-# ac_fn_c_try_link LINENO
-# -----------------------
-# Try to link conftest.$ac_ext, and return whether this succeeded.
-ac_fn_c_try_link ()
-{
-  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  rm -f conftest.$ac_objext conftest$ac_exeext
-  if { { ac_try="$ac_link"
-case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
-  (eval "$ac_link") 2>conftest.err
-  ac_status=$?
-  if test -s conftest.err; then
-    grep -v '^ *+' conftest.err >conftest.er1
-    cat conftest.er1 >&5
-    mv -f conftest.er1 conftest.err
-  fi
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; } && {
-	 test -z "$ac_c_werror_flag" ||
-	 test ! -s conftest.err
-       } && test -s conftest$ac_exeext && {
-	 test "$cross_compiling" = yes ||
-	 test -x conftest$ac_exeext
-       }; then :
-  ac_retval=0
-else
-  $as_echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-	ac_retval=1
-fi
-  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
-  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
-  # interfere with the next link command; also delete a directory that is
-  # left behind by Apple's compiler.  We do this before executing the actions.
-  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
-  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
-  as_fn_set_status $ac_retval
-
-} # ac_fn_c_try_link
-
 # ac_fn_c_check_type LINENO TYPE VAR INCLUDES
 # -------------------------------------------
 # Tests whether TYPE exists after having included INCLUDES, setting cache
@@ -1856,6 +1808,52 @@ $as_echo "$ac_res" >&6; }
 
 } # ac_fn_c_check_type
 
+# ac_fn_c_try_link LINENO
+# -----------------------
+# Try to link conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_link ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest$ac_exeext
+  if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 test -x conftest$ac_exeext
+       }; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1
+fi
+  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
+  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
+  # interfere with the next link command; also delete a directory that is
+  # left behind by Apple's compiler.  We do this before executing the actions.
+  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_link
+
 # ac_fn_c_check_func LINENO FUNC VAR
 # ----------------------------------
 # Tests whether FUNC exists, setting the cache variable VAR accordingly
@@ -5827,71 +5825,6 @@ fi
 # Set the 'development' global.
 . $srcdir/../../bfd/development.sh
 
-# Enable -lmcheck by default (it provides cheap-enough memory
-# mangling), but turn it off for releases.
-if $development; then
-  libmcheck_default=yes
-else
-  libmcheck_default=no
-fi
-
-  # Check whether --enable-libmcheck was given.
-if test "${enable_libmcheck+set}" = set; then :
-  enableval=$enable_libmcheck; case "${enableval}" in
-      yes | y) ENABLE_LIBMCHECK="yes" ;;
-      no | n)  ENABLE_LIBMCHECK="no" ;;
-      *) as_fn_error $? "bad value ${enableval} for --enable-libmcheck" "$LINENO" 5 ;;
-    esac
-fi
-
-
-  if test -z "${ENABLE_LIBMCHECK}"; then
-    ENABLE_LIBMCHECK=${libmcheck_default}
-  fi
-
-  if test "$ENABLE_LIBMCHECK" = "yes" ; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for main in -lmcheck" >&5
-$as_echo_n "checking for main in -lmcheck... " >&6; }
-if ${ac_cv_lib_mcheck_main+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_check_lib_save_LIBS=$LIBS
-LIBS="-lmcheck  $LIBS"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-
-int
-main ()
-{
-return main ();
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_mcheck_main=yes
-else
-  ac_cv_lib_mcheck_main=no
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
-LIBS=$ac_check_lib_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_mcheck_main" >&5
-$as_echo "$ac_cv_lib_mcheck_main" >&6; }
-if test "x$ac_cv_lib_mcheck_main" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_LIBMCHECK 1
-_ACEOF
-
-  LIBS="-lmcheck $LIBS"
-
-fi
-
-  fi
-
-
 
 # Check whether we will enable the inclusion of unit tests when
 # compiling GDB.
diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac
index 574b7c5b2879..0009aac9f207 100644
--- a/gdb/gdbserver/configure.ac
+++ b/gdb/gdbserver/configure.ac
@@ -45,15 +45,6 @@ AC_HEADER_STDC
 # Set the 'development' global.
 . $srcdir/../../bfd/development.sh
 
-# Enable -lmcheck by default (it provides cheap-enough memory
-# mangling), but turn it off for releases.
-if $development; then
-  libmcheck_default=yes
-else
-  libmcheck_default=no
-fi
-GDB_AC_LIBMCHECK(${libmcheck_default})
-
 GDB_AC_SELFTEST([
   srv_selftest_objs="gdbsupport/selftest.o"
 ])
diff --git a/gdb/libmcheck.m4 b/gdb/libmcheck.m4
deleted file mode 100644
index 692a5c868925..000000000000
--- a/gdb/libmcheck.m4
+++ /dev/null
@@ -1,43 +0,0 @@
-dnl Copyright (C) 2012-2019 Free Software Foundation, Inc.
-dnl
-dnl This file is part of GDB.
-dnl
-dnl This program is free software; you can redistribute it and/or modify
-dnl it under the terms of the GNU General Public License as published by
-dnl the Free Software Foundation; either version 3 of the License, or
-dnl (at your option) any later version.
-dnl
-dnl This program is distributed in the hope that it will be useful,
-dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
-dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-dnl GNU General Public License for more details.
-dnl
-dnl You should have received a copy of the GNU General Public License
-dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-dnl GDB_AC_LIBMCHECK([DEFAULT])
-dnl Provide an --enable-libmcheck/--disable-libmcheck set of options
-dnl allowing a user to enable this option even when building releases,
-dnl or to disable it when building a snapshot.
-dnl DEFAULT (yes/no) is used as default if the user doesn't set
-dnl the option explicitly.
-
-AC_DEFUN([GDB_AC_LIBMCHECK],
-[
-  AC_ARG_ENABLE(libmcheck,
-    AS_HELP_STRING([--enable-libmcheck],
-		   [Try linking with -lmcheck if available]),
-    [case "${enableval}" in
-      yes | y) ENABLE_LIBMCHECK="yes" ;;
-      no | n)  ENABLE_LIBMCHECK="no" ;;
-      *) AC_MSG_ERROR(bad value ${enableval} for --enable-libmcheck) ;;
-    esac])
-
-  if test -z "${ENABLE_LIBMCHECK}"; then
-    ENABLE_LIBMCHECK=[$1]
-  fi
-
-  if test "$ENABLE_LIBMCHECK" = "yes" ; then
-    AC_CHECK_LIB(mcheck, main)
-  fi
-])
diff --git a/gdb/top.c b/gdb/top.c
index 60f81b3bf854..a9f9a384f7e1 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1462,15 +1462,6 @@ This GDB was configured as follows:\n\
              --without-intel-pt\n\
 "));
 #endif
-#if HAVE_LIBMCHECK
-    fprintf_filtered (stream, _("\
-             --enable-libmcheck\n\
-"));
-#else
-    fprintf_filtered (stream, _("\
-             --disable-libmcheck\n\
-"));
-#endif
 #if HAVE_LIBMPFR
     fprintf_filtered (stream, _("\
              --with-mpfr\n\
