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[Qemu-devel] [PATCH] configure: fix sanitizers' test program to mend ASa
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH] configure: fix sanitizers' test program to mend ASan detection |
Date: |
Tue, 20 Feb 2018 20:03:15 -0500 |
Commit 218bb57 ("build-sys: check static linking of UBSAN", 2018-02-13)
adds a small test program to check whether ubsan works even when
configuring with --static. This added program is used to
detect all sanitizers, which breaks ASan's detection since the
compilation fails with -fsanitize=address, at least with gcc 5.4.0
and 7.2.0:
qemu-conf.c: In function ‘main’:
qemu-conf.c:3:20: error: integer overflow in expression [-Werror=overflow]
return INT32_MIN / -1;
^
cc1: all warnings being treated as errors
Fix it by:
- Changing the test program to one that incurs undefined behaviour that isn't
detected at compile-time, even with -fsanitize=address.
- To be extra safe (since compilers might evolve and eventually figure out
the UB at compile-time), use this newly-added test only when checking
for UBSan; use the skeleton otherwise.
Signed-off-by: Emilio G. Cota <address@hidden>
---
configure | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/configure b/configure
index 913e148..56f647f 100755
--- a/configure
+++ b/configure
@@ -5306,13 +5306,13 @@ fi
##########################################
# checks for sanitizers
-# we could use a simple skeleton for flags checks, but this also
-# detect the static linking issue of ubsan, see also:
+# Use this program to detect the static linking issue of ubsan; see
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84285
cat > $TMPC << EOF
-#include <stdint.h>
-int main(void) {
- return INT32_MIN / -1;
+int main(int argc, char **argv) {
+ int k = 0x7fffffff;
+ k += argc;
+ return 0;
}
EOF
@@ -5322,12 +5322,16 @@ have_asan_iface_h=no
have_asan_iface_fiber=no
if test "$sanitizers" = "yes" ; then
+ if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then
+ have_ubsan=yes
+ fi
+
+ # Use the skeleton for all other sanitizer checks
+ write_c_skeleton
+
if compile_prog "$CPU_CFLAGS -Werror -fsanitize=address" ""; then
have_asan=yes
fi
- 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
--
2.7.4
- [Qemu-devel] [PATCH] configure: fix sanitizers' test program to mend ASan detection,
Emilio G. Cota <=