[PATCH] tools/lib/perf: Fix -Werror=alloc-size-larger-than in cpumap.c

[Athira Rajeev]

> On 14 Apr 2025, at 7:08 AM, Madhavan Srinivasan <maddy at linux.ibm.com> wrote:
> 
> 
> 
> On 4/7/25 5:38 PM, Venkat Rao Bagalkote wrote:
>> 
>> On 07/04/25 12:10 am, Athira Rajeev wrote:
>>> 
>>>> On 6 Apr 2025, at 10:04 PM, Likhitha Korrapati <likhitha at linux.ibm.com> wrote:
>>>> 
>>>> perf build break observed when using gcc 13-3 (FC39 ppc64le)
>>>> with the following error.
>>>> 
>>>> cpumap.c: In function 'perf_cpu_map__merge':
>>>> cpumap.c:414:20: error: argument 1 range [18446744069414584320, 18446744073709551614] exceeds maximum object size 9223372036854775807 [-Werror=alloc-size-larger-than=]
>>>>   414 |         tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
>>>>       |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> In file included from cpumap.c:4:
>>>> /usr/include/stdlib.h:672:14: note: in a call to allocation function 'malloc' declared here
>>>>   672 | extern void *malloc (size_t __size) __THROW __attribute_malloc__
>>>>       |              ^~~~~~
>>>> cc1: all warnings being treated as errors
>>>> 
>>>> Error happens to be only in gcc13-3 and not in latest gcc 14.
>>>> Even though git-bisect pointed bad commit as:
>>>> 'commit f5b07010c13c ("libperf: Don't remove -g when EXTRA_CFLAGS are used")',
>>>> issue is with tmp_len being "int". It holds number of cpus and making
>>>> it "unsigned int" fixes the issues.
>>>> 
>>>> After the fix:
>>>> 
>>>>   CC      util/pmu-flex.o
>>>>   CC      util/expr-flex.o
>>>>   LD      util/perf-util-in.o
>>>>   LD      perf-util-in.o
>>>>   AR      libperf-util.a
>>>>   LINK    perf
>>>>   GEN     python/perf.cpython-312-powerpc64le-linux-gnu.so
>>>> 
>>>> Signed-off-by: Likhitha Korrapati <likhitha at linux.ibm.com>
>>> Looks good to me
>>> 
>>> Reviewed-by: Athira Rajeev <atrajeev at linux.ibm.com>
>> 
>> Tested this patch on perf-tools-next repo, and this patch fixes the issue.
>> 
>> Tested-by: Venkat Rao Bagalkote <venkat88 at linux.ibm.com>
>> 
>> 
> 
> Arnaldo, Namhyung,
> 
> can you consider pulling this fix? since it is breaking the build in gcc13-3 or
> if you have any comments do let us know.
> 
> Thanks
> Maddy

Hi,

Can we get this pulled in if the change looks good ? This is breaking build on gcc-13-3 
Looking for feedback on this patch..

Thanks
Athira
> 
> 
> 
>> Regards,
>> 
>> Venkat.
>> 
>>> 
>>> Thanks
>>> Athira
>>>> ---
>>>> tools/lib/perf/cpumap.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>> 
>>>> diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
>>>> index 4454a5987570..c7c784e18225 100644
>>>> --- a/tools/lib/perf/cpumap.c
>>>> +++ b/tools/lib/perf/cpumap.c
>>>> @@ -398,7 +398,7 @@ bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu
>>>> int perf_cpu_map__merge(struct perf_cpu_map **orig, struct perf_cpu_map *other)
>>>> {
>>>> struct perf_cpu *tmp_cpus;
>>>> - int tmp_len;
>>>> + unsigned int tmp_len;
>>>> int i, j, k;
>>>> struct perf_cpu_map *merged;
>>>> 
>>>> -- 
>>>> 2.43.5