| Message ID | 1519174995-1039-1-git-send-email-cota@braap.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi On Wed, Feb 21, 2018 at 2:03 AM, Emilio G. Cota <cota@braap.org> wrote: > 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 I sent a patch a few days ago: "[PATCH 1/6] build-sys: fix -fsanitize=address check" > > 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 <cota@braap.org> > --- > 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 >
On Wed, Feb 21, 2018 at 10:12:28 +0100, Marc-André Lureau wrote: > I sent a patch a few days ago: > "[PATCH 1/6] build-sys: fix -fsanitize=address check" Ouch, I missed that. Please disregard my patch. Thanks, Emilio
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
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 <cota@braap.org> --- configure | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)