On Fri, Apr 25, 2025 at 08:19:02PM +0530, Athira Rajeev wrote:
> > On 14 Apr 2025, at 7:08 AM, Madhavan Srinivasan <ma...@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 <likhi...@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 <likhi...@linux.ibm.com>
> >>> Looks good to me
> >>> Reviewed-by: Athira Rajeev <atraj...@linux.ibm.com>
> >> Tested this patch on perf-tools-next repo, and this patch fixes the issue.
> >> Tested-by: Venkat Rao Bagalkote <venka...@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.
This isn't the only place in that file where this pattern exists:
⬢ [acme@toolbx perf-tools-next]$ grep malloc tools/lib/perf/cpumap.c
cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
⬢ [acme@toolbx perf-tools-next]$
struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus)
{
RC_STRUCT(perf_cpu_map) *cpus;
struct perf_cpu_map *result;
if (nr_cpus == 0)
return NULL;
cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
int perf_cpu_map__merge(struct perf_cpu_map **orig, struct perf_cpu_map *other)
{
struct perf_cpu *tmp_cpus;
int tmp_len;
int i, j, k;
struct perf_cpu_map *merged;
if (perf_cpu_map__is_subset(*orig, other))
return 0;
if (perf_cpu_map__is_subset(other, *orig)) {
perf_cpu_map__put(*orig);
*orig = perf_cpu_map__get(other);
return 0;
}
tmp_len = __perf_cpu_map__nr(*orig) + __perf_cpu_map__nr(other);
tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
struct perf_cpu_map *other)
{
struct perf_cpu *tmp_cpus;
int tmp_len;
int i, j, k;
struct perf_cpu_map *merged = NULL;
if (perf_cpu_map__is_subset(other, orig))
return perf_cpu_map__get(orig);
if (perf_cpu_map__is_subset(orig, other))
return perf_cpu_map__get(other);
tmp_len = max(__perf_cpu_map__nr(orig), __perf_cpu_map__nr(other));
tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
I'm trying to figure out why its only in perf_cpu_map__merge() that this
triggers :-\
Maybe that max() call in perf_cpu_map__intersect() somehow makes the
compiler happy.
And in perf_cpu_map__alloc() all calls seems to validate it.
But wouldn't turning this into a calloc() be better?
Like:
diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index 4454a5987570cfbc..99d21618a252ac0e 100644
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -411,7 +411,7 @@ int perf_cpu_map__merge(struct perf_cpu_map **orig, struct
perf_cpu_map *other)
}
tmp_len = __perf_cpu_map__nr(*orig) + __perf_cpu_map__nr(other);
- tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
+ tmp_cpus = calloc(tmp_len, sizeof(struct perf_cpu));
if (!tmp_cpus)
return -ENOMEM;
⬢ [acme@toolbx perf-tools-next]$
And better, do the max size that the compiler is trying to help us
catch?
- Arnaldo
