On Wed, Oct 16, 2024 at 5:30 AM Athira Rajeev <atraj...@linux.vnet.ibm.com> wrote: > > > > > On 14 Oct 2024, at 10:56 PM, Namhyung Kim <namhy...@kernel.org> wrote: > > > > Hello Athira, > > > > On Sun, Oct 13, 2024 at 11:07:42PM +0530, Athira Rajeev wrote: > >> perf fails to compile on systems with GCC version11 > >> as below: > >> > >> In file included from /usr/include/string.h:519, > >> from > >> /home/athir/perf-tools-next/tools/include/linux/bitmap.h:5, > >> from /home/athir/perf-tools-next/tools/perf/util/pmu.h:5, > >> from > >> /home/athir/perf-tools-next/tools/perf/util/evsel.h:14, > >> from > >> /home/athir/perf-tools-next/tools/perf/util/evlist.h:14, > >> from tests/tool_pmu.c:3: > >> In function ‘strncpy’, > >> inlined from ‘do_test’ at tests/tool_pmu.c:25:3: > >> /usr/include/bits/string_fortified.h:95:10: error: ‘__builtin_strncpy’ > >> specified bound 128 equals destination size [-Werror=stringop-truncation] > >> 95 | return __builtin___strncpy_chk (__dest, __src, __len, > >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> 96 | __glibc_objsize (__dest)); > >> | ~~~~~~~~~~~~~~~~~~~~~~~~~ > >> > >> The compile error is from strncpy refernce in do_test: > >> strncpy(str, tool_pmu__event_to_str(ev), sizeof(str)); > >> > >> This behaviour is not observed with GCC version 8, but observed > >> with GCC version 11 . This is message from gcc for detecting > >> truncation while using strncpu. Use snprintf instead of strncpy > >> here to be safe. > >> > >> Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com> > > > > I found this issue now and thanks for the quick fix. I will push to > > perf-tools-next soon. > > > > Thanks, > > Namhyung > > > > Sure > > Thanks Namhyung for pulling in the change > > Athira
Thanks for the fixes. As this is test code I don't think performance, style, etc. matter much. The GCC strncpy warnings are annoying imo, I'm not sure it makes sense for them to be enabled. I see in the kernel lots of "sizeof(foo)-1" as a workaround. strlcpy looks like a better alternative but it gets a checkpatch warning as in the kernel strscpy is preferred. Perhaps we should create a strscpy shim. Thanks, Ian > >> --- > >> tools/perf/tests/tool_pmu.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/tools/perf/tests/tool_pmu.c b/tools/perf/tests/tool_pmu.c > >> index 94d0dd8fd3cb..297cc8c55579 100644 > >> --- a/tools/perf/tests/tool_pmu.c > >> +++ b/tools/perf/tests/tool_pmu.c > >> @@ -22,7 +22,7 @@ static int do_test(enum tool_pmu_event ev, bool with_pmu) > >> if (with_pmu) > >> snprintf(str, sizeof(str), "tool/%s/", tool_pmu__event_to_str(ev)); > >> else > >> - strncpy(str, tool_pmu__event_to_str(ev), sizeof(str)); > >> + snprintf(str, sizeof(str), "%s", tool_pmu__event_to_str(ev)); > >> > >> parse_events_error__init(&err); > >> ret = parse_events(evlist, str, &err); > >> -- > >> 2.43.5 > >
