[4/5] misc: enable thread sanitizer if the builder wants it

diff --git a/MCONFIG.in b/MCONFIG.in
index 1344511..c3b3740 100644
--- a/MCONFIG.in
+++ b/MCONFIG.in
@@ -81,8 +81,8 @@  SYSTEMD_SYSTEM_UNIT_DIR = @systemd_system_unit_dir@
 @ifNotGNUmake@ CHECK_CMD=true
 @ifNotGNUmake@ CPPCHECK_CMD=true
 
-SANITIZER_CFLAGS = @lto_cflags@ @ubsan_cflags@ @addrsan_cflags@
-SANITIZER_LDFLAGS = @lto_ldflags@ @ubsan_ldflags@ @addrsan_ldflags@
+SANITIZER_CFLAGS = @lto_cflags@ @ubsan_cflags@ @addrsan_cflags@ @threadsan_cflags@
+SANITIZER_LDFLAGS = @lto_ldflags@ @ubsan_ldflags@ @addrsan_ldflags@ @threadsan_ldflags@
 
 CC = @CC@
 BUILD_CC = @BUILD_CC@
diff --git a/configure b/configure
index 31fe8ca..c278ddb 100755
--- a/configure
+++ b/configure
@@ -653,6 +653,9 @@  E2SCRUB_CMT
 UNIX_CMT
 CYGWIN_CMT
 LINUX_CMT
+threadsan_ldflags
+threadsan_cflags
+have_threadsan
 addrsan_ldflags
 addrsan_cflags
 have_addrsan
@@ -917,6 +920,7 @@  enable_fuse2fs
 enable_lto
 enable_ubsan
 enable_addrsan
+enable_threadsan
 with_multiarch
 with_udev_rules_dir
 with_crond_dir
@@ -1598,6 +1602,7 @@  Optional Features:
   --enable-lto		  enable link time optimization
   --enable-ubsan	  enable undefined behavior sanitizer
   --enable-addrsan	  enable address sanitizer
+  --enable-threadsan	  enable thread sanitizer
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -13969,6 +13974,57 @@  fi
 if test "$enable_addrsan" = "yes" && test "$have_addrsan" != "yes"; then
 	as_fn_error $? "ADDRSAN not supported by compiler." "$LINENO" 5
 fi
+# Check whether --enable-threadsan was given.
+if test "${enable_threadsan+set}" = set; then :
+  enableval=$enable_threadsan;
+else
+  enable_threadsan=no
+fi
+
+if test "$enable_threadsan" = "yes" || test "$enable_threadsan" = "probe"; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if C compiler supports THREADSAN" >&5
+$as_echo_n "checking if C compiler supports THREADSAN... " >&6; }
+	OLD_CFLAGS="$CFLAGS"
+	OLD_LDFLAGS="$LDFLAGS"
+	THREADSAN_FLAGS="-fsanitize=thread"
+	CFLAGS="$CFLAGS $THREADSAN_FLAGS"
+	LDFLAGS="$LDFLAGS $THREADSAN_FLAGS"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+		threadsan_cflags=$THREADSAN_FLAGS
+		threadsan_ldflags=$THREADSAN_FLAGS
+		have_threadsan=yes
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+	CFLAGS="${OLD_CFLAGS}"
+	LDFLAGS="${OLD_LDFLAGS}"
+
+
+
+fi
+if test "$enable_threadsan" = "yes" && test "$have_threadsan" != "yes"; then
+	as_fn_error $? "THREADSAN not supported by compiler." "$LINENO" 5
+fi
+if test "$have_threadsan" = "yes" && test "$have_addrsan" = "yes"; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: ADDRSAN and THREADSAN are not known to work together." >&5
+$as_echo "$as_me: WARNING: ADDRSAN and THREADSAN are not known to work together." >&2;}
+fi
 LINUX_CMT="#"
 CYGWIN_CMT="#"
 UNIX_CMT=
diff --git a/configure.ac b/configure.ac
index e02bdea..1cc7420 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1385,6 +1385,37 @@  if test "$enable_addrsan" = "yes" && test "$have_addrsan" != "yes"; then
 	AC_MSG_ERROR([ADDRSAN not supported by compiler.])
 fi
 dnl
+dnl Enable THREADSAN for all packages
+dnl
+AC_ARG_ENABLE([threadsan],
+[  --enable-threadsan	  enable thread sanitizer],,
+enable_threadsan=no)
+if test "$enable_threadsan" = "yes" || test "$enable_threadsan" = "probe"; then
+	AC_MSG_CHECKING([if C compiler supports THREADSAN])
+	OLD_CFLAGS="$CFLAGS"
+	OLD_LDFLAGS="$LDFLAGS"
+	THREADSAN_FLAGS="-fsanitize=thread"
+	CFLAGS="$CFLAGS $THREADSAN_FLAGS"
+	LDFLAGS="$LDFLAGS $THREADSAN_FLAGS"
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
+		[AC_MSG_RESULT([yes])]
+		[threadsan_cflags=$THREADSAN_FLAGS]
+		[threadsan_ldflags=$THREADSAN_FLAGS]
+		[have_threadsan=yes],
+		[AC_MSG_RESULT([no])])
+	CFLAGS="${OLD_CFLAGS}"
+	LDFLAGS="${OLD_LDFLAGS}"
+	AC_SUBST(have_threadsan)
+	AC_SUBST(threadsan_cflags)
+	AC_SUBST(threadsan_ldflags)
+fi
+if test "$enable_threadsan" = "yes" && test "$have_threadsan" != "yes"; then
+	AC_MSG_ERROR([THREADSAN not supported by compiler.])
+fi
+if test "$have_threadsan" = "yes" && test "$have_addrsan" = "yes"; then
+	AC_MSG_WARN([ADDRSAN and THREADSAN are not known to work together.])
+fi
+dnl
 dnl OS-specific uncomment control
 dnl
 LINUX_CMT="#"
diff --git a/debian/rules b/debian/rules
index f4135e8..6f694dd 100755
--- a/debian/rules
+++ b/debian/rules
@@ -165,7 +165,7 @@  endif
 BACKTRACE_CONF_FLAGS ?= $(shell if ${debdir}/scripts/test-backtrace ; then echo --disable-backtrace ; fi)
 
 COMMON_CONF_FLAGS = --enable-lto --disable-ubsan --disable-addrsan \
-	--disable-e2initrd-helper \
+	--disable-threadsan --disable-e2initrd-helper \
 	--infodir=/usr/share/info  --enable-symlink-install \
 	--with-multiarch=$(DEB_HOST_MULTIARCH) \
 	$(BACKTRACE_CONF_FLAGS) $(UTIL_CONF_FLAGS)