Re: [PATCH bpf-next v3 1/1] samples/bpf: Add -fsanitize=bounds to userspace programs

[Jiri Olsa <olsajiri@gmail.com>]

On Wed, Sep 27, 2023 at 06:19:10PM -0500, ruowenq2@illinois.edu wrote:
> 
> 
> On 9/27/23 6:03 AM, Jiri Olsa <olsajiri@gmail.com> wrote:
> > On Tue, Sep 26, 2023 at 11:50:30PM -0500, ruowenq2@illinois.edu wrote:
> > > From: Ruowen Qin <ruowenq2@illinois.edu>
> > >
> > > The sanitizer flag, which is supported by both clang and gcc, would make
> > > it easier to debug array index out-of-bounds problems in these programs.
> > >
> > > Make the Makfile smarter to detect ubsan support from the compiler and
> > > add the '-fsanitize=bounds' accordingly.
> > >
> > > Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
> > > Signed-off-by: Jinghao Jia <jinghao@linux.ibm.com>
> > > Signed-off-by: Jinghao Jia <jinghao7@illinois.edu>
> > > Signed-off-by: Ruowen Qin <ruowenq2@illinois.edu>
> > > ---
> > >   samples/bpf/Makefile | 3 +++
> > >   1 file changed, 3 insertions(+)
> > >
> > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > > index 6c707ebcebb9..90af76fa9dd8 100644
> > > --- a/samples/bpf/Makefile
> > > +++ b/samples/bpf/Makefile
> > > @@ -169,6 +169,9 @@ endif
> > >   TPROGS_CFLAGS += -Wall -O2
> > >   TPROGS_CFLAGS += -Wmissing-prototypes
> > >   TPROGS_CFLAGS += -Wstrict-prototypes
> > > +TPROGS_CFLAGS += $(call try-run,\
> > > +	printf "int main() { return 0; }" |\
> > > +	$(CC) -Werror -fsanitize=bounds -x c - -o "$$TMP",-fsanitize=bounds,)
> > 
> > I haven't checked deeply, but could we use just cc-option? looks simpler
> > 
> > TPROGS_CFLAGS += $(call cc-option, -fsanitize=bounds)
> > 
> > jirka
> 
> Hi, thanks for your quick reply! When checking for flags, cc-option does not execute the linker, but on Fedora, an error appears and stating that "/usr/lib64/libubsan.so.1.0.0" cannot be found during linking. So I try this seemingly cumbersome way.

I see, there's also ld-option, would that work?

jirka

> 
> Ruowen
> 
> > >   >   TPROGS_CFLAGS += -I$(objtree)/usr/include
> > >   TPROGS_CFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
> > > -- > 2.42.0
> > >
> > >
> >