Messages in this thread | | | From | David Carrillo-Cisneros <> | Date | Tue, 11 Apr 2017 11:34:04 -0700 | Subject | Re: [PATCH 6/7] perf tool: protect empty evlists |
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I did my best to fix those issues in perf inject and perf report, but yeah, other commands may have issues.
On Tue, Apr 11, 2017 at 11:12 AM, Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > Em Mon, Apr 10, 2017 at 01:14:31PM -0700, David Carrillo-Cisneros escreveu: >> A common pattern in in pipe-mode bugs is accessing an empty evlist. >> Return NULL to make it easier to catch this problems. > > This one is far reaching, we need to take care handling all places using > these functions, albeit probably most cases will always have an evsel, I > looked at builtin-top.c for instance, and I think we need to be more > careful here, will leave this for later. > > - Arnaldo > >> Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> >> --- >> tools/perf/util/evlist.h | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h >> index 39942995f537..ba4788462325 100644 >> --- a/tools/perf/util/evlist.h >> +++ b/tools/perf/util/evlist.h >> @@ -257,11 +257,15 @@ void perf_evlist__splice_list_tail(struct perf_evlist *evlist, >> >> static inline struct perf_evsel *perf_evlist__first(struct perf_evlist *evlist) >> { >> + if (list_empty(&evlist->entries)) >> + return NULL; >> return list_entry(evlist->entries.next, struct perf_evsel, node); >> } >> >> static inline struct perf_evsel *perf_evlist__last(struct perf_evlist *evlist) >> { >> + if (list_empty(&evlist->entries)) >> + return NULL; >> return list_entry(evlist->entries.prev, struct perf_evsel, node); >> } >> >> -- >> 2.12.2.715.g7642488e1d-goog
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