On 9/28/23 3:15 AM, Jiri Olsa wrote:
> On Wed, Sep 27, 2023 at 06:19:10PM -0500, ruowenq2@xxxxxxxxxxxx wrote:
>>
>>
>> On 9/27/23 6:03 AM, Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
>>> On Tue, Sep 26, 2023 at 11:50:30PM -0500, ruowenq2@xxxxxxxxxxxx wrote:
>>>> From: Ruowen Qin <ruowenq2@xxxxxxxxxxxx>
>>>>
>>>> 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@xxxxxxxxxxxxx>
>>>> Signed-off-by: Jinghao Jia <jinghao@xxxxxxxxxxxxx>
>>>> Signed-off-by: Jinghao Jia <jinghao7@xxxxxxxxxxxx>
>>>> Signed-off-by: Ruowen Qin <ruowenq2@xxxxxxxxxxxx>
>>>> ---
>>>> 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 += $(call cc-option, -fsanitize=bounds)
>>>
>>> jirka
>>
>> Hi, thanks for your quick reply! When checking for flags, cc-option does not execute the linker, but on Fedora, an error appears and stating that "/usr/lib64/libubsan.so.1.0.0" cannot be found during linking. So I try this seemingly cumbersome way.
>
> I see, there's also ld-option, would that work?
>
> jirka
>
IMHO I don't think ld-option would solve the problem. It directly sends the
flag to the linker but -fsanitize=bounds is a compiler flag, not a linker
flag.
Basically, what's special about this case is that the feature we want to
probe is behind a gcc/clang flag but we do not know whether it is supported
until link time (e.g. the sanitizer library is missing on Fedora so we get
a link error).
--Jinghao
>>
>> Ruowen
>>
>>>> > TPROGS_CFLAGS += -I$(objtree)/usr/include
>>>> TPROGS_CFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
>>>> -- > 2.42.0
>>>>
>>>>
>>>
