[PATCH 09/11] perf tools: Dont stop PMU parsing on alias parse error

From: Arnaldo Carvalho de Melo
Date: Tue Feb 23 2016 - 15:02:44 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

When an error happens during alias parsing currently the complete
parsing of all attributes of the PMU is stopped. This is breaks old perf
on a newer kernel that may have not-yet-know alias attributes (such as
.scale or .per-pkg).

Continue when some attribute is unparseable.

This is IMHO a stable candidate and should be backported to older
versions to avoid problems with newer kernels.

v2: Print warnings when something goes wrong.
v3: Change warning to debug output

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v3.6+
Link: http://lkml.kernel.org/r/1455749095-18358-1-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/pmu.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index cf59fbaee491..ce61f79dbaae 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -284,13 +284,12 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
{
struct dirent *evt_ent;
DIR *event_dir;
- int ret = 0;

event_dir = opendir(dir);
if (!event_dir)
return -EINVAL;

- while (!ret && (evt_ent = readdir(event_dir))) {
+ while ((evt_ent = readdir(event_dir))) {
char path[PATH_MAX];
char *name = evt_ent->d_name;
FILE *file;
@@ -306,17 +305,19 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)

snprintf(path, PATH_MAX, "%s/%s", dir, name);

- ret = -EINVAL;
file = fopen(path, "r");
- if (!file)
- break;
+ if (!file) {
+ pr_debug("Cannot open %s\n", path);
+ continue;
+ }

- ret = perf_pmu__new_alias(head, dir, name, file);
+ if (perf_pmu__new_alias(head, dir, name, file) < 0)
+ pr_debug("Cannot set up %s\n", name);
fclose(file);
}

closedir(event_dir);
- return ret;
+ return 0;
}

/*
--
2.5.0