perf record: Robustify perf_event__synth_time_conv()

It is possible that all events in an evlist are overwritable.
perf_event__synth_time_conv() should not crash in this case.
record__pick_pc() is used to check avaliability.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464056944-166978-3-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Wang Nan 2016-05-24 02:28:59 +00:00 committed by Arnaldo Carvalho de Melo
parent 792d48b4cf
commit c45628b0a3
2 changed files with 10 additions and 1 deletions

View File

@ -62,6 +62,8 @@ int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
struct perf_tsc_conversion tc;
int err;
if (!pc)
return 0;
err = perf_read_tsc_conversion(pc, &tc);
if (err == -EOPNOTSUPP)
return 0;

View File

@ -655,6 +655,13 @@ perf_event__synth_time_conv(const struct perf_event_mmap_page *pc __maybe_unused
return 0;
}
static const struct perf_event_mmap_page *record__pick_pc(struct record *rec)
{
if (rec->evlist && rec->evlist->mmap && rec->evlist->mmap[0].base)
return rec->evlist->mmap[0].base;
return NULL;
}
static int record__synthesize(struct record *rec)
{
struct perf_session *session = rec->session;
@ -692,7 +699,7 @@ static int record__synthesize(struct record *rec)
}
}
err = perf_event__synth_time_conv(rec->evlist->mmap[0].base, tool,
err = perf_event__synth_time_conv(record__pick_pc(rec), tool,
process_synthesized_event, machine);
if (err)
goto out;