ucontext: annotate coroutine stack for ASAN

It helps ASAN to detect more leaks on coroutine stacks, and to get rid
of some extra warnings.

Before:

tests/test-coroutine -p
/basic/lifecycle
/basic/lifecycle: ==20781==WARNING: ASan doesn't fully support
makecontext/swapcontext functions and may produce false positives in
some cases!
==20781==WARNING: ASan is ignoring requested __asan_handle_no_return:
stack top: 0x7ffcb184d000; bottom 0x7ff6c4cfd000; size: 0x0005ecb50000
(25446121472)
False positive error reports may follow
For details see https://github.com/google/sanitizers/issues/189
OK

After:

tests/test-coroutine -p /basic/lifecycle
/basic/lifecycle: ==21110==WARNING: ASan doesn't fully support
makecontext/swapcontext functions and may produce false positives in
some cases!
OK

A similar work would need to be done for sigaltstack & windows fibers
to have similar coverage. Since ucontext is preferred, I didn't bother
checking the other coroutine implementations for now.

Update travis to fix the build with ASAN annotations.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180116151152.4040-4-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/configure b/configure
index 35147ad..529aad5 100755
--- a/configure
+++ b/configure
@@ -5213,6 +5213,8 @@ write_c_skeleton
 
 have_asan=no
 have_ubsan=no
+have_asan_iface_h=no
+have_asan_iface_fiber=no
 
 if test "$sanitizers" = "yes" ; then
   if compile_prog "$CPU_CFLAGS -Werror -fsanitize=address" ""; then
@@ -5221,12 +5223,29 @@ if test "$sanitizers" = "yes" ; then
   if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then
       have_ubsan=yes
   fi
+
+  if check_include "sanitizer/asan_interface.h" ; then
+      have_asan_iface_h=yes
+  fi
+
+  cat > $TMPC << EOF
+#include <sanitizer/asan_interface.h>
+int main(void) {
+  __sanitizer_start_switch_fiber(0, 0, 0);
+  return 0;
+}
+EOF
+  if compile_prog "$CPU_CFLAGS -Werror -fsanitize=address" "" ; then
+      have_asan_iface_fiber=yes
+  fi
 fi
 
 ##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs
 
+write_c_skeleton
+
 if test "$gcov" = "yes" ; then
   CFLAGS="-fprofile-arcs -ftest-coverage -g $CFLAGS"
   LDFLAGS="-fprofile-arcs -ftest-coverage $LDFLAGS"
@@ -5249,6 +5268,13 @@ fi
 
 if test "$have_asan" = "yes"; then
   CFLAGS="-fsanitize=address $CFLAGS"
+  if test "$have_asan_iface_h" = "no" ; then
+      echo "ASAN build enabled, but ASAN header missing." \
+           "Without code annotation, the report may be inferior."
+  elif test "$have_asan_iface_fiber" = "no" ; then
+      echo "ASAN build enabled, but ASAN header is too old." \
+           "Without code annotation, the report may be inferior."
+  fi
 fi
 if test "$have_ubsan" = "yes"; then
   CFLAGS="-fsanitize=undefined $CFLAGS"
@@ -6237,6 +6263,10 @@ if test "$valgrind_h" = "yes" ; then
   echo "CONFIG_VALGRIND_H=y" >> $config_host_mak
 fi
 
+if test "$have_asan_iface_fiber" = "yes" ; then
+    echo "CONFIG_ASAN_IFACE_FIBER=y" >> $config_host_mak
+fi
+
 if test "$has_environ" = "yes" ; then
   echo "CONFIG_HAS_ENVIRON=y" >> $config_host_mak
 fi