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Subject[PATCH v2 2/2] perf tools: Fix pattern matching for same substring in different pmu type
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Some different pmu types may have same substring. For example,
on Icelake server, we have pmu types "uncore_imc" and
"uncore_imc_free_running". Both pmu types have substring "uncore_imc".
But the parser would wrongly think they are the same pmu type.

We enable an imc event,
perf stat -e uncore_imc/event=0xe3/ -a -- sleep 1

Perf actually expands the event to:
uncore_imc_0/event=0xe3/
uncore_imc_1/event=0xe3/
uncore_imc_2/event=0xe3/
uncore_imc_3/event=0xe3/
uncore_imc_4/event=0xe3/
uncore_imc_5/event=0xe3/
uncore_imc_6/event=0xe3/
uncore_imc_7/event=0xe3/
uncore_imc_free_running_0/event=0xe3/
uncore_imc_free_running_1/event=0xe3/
uncore_imc_free_running_3/event=0xe3/
uncore_imc_free_running_4/event=0xe3/

That's because the "uncore_imc_free_running" matches the
pattern "uncore_imc*".

Now we check that the last characters of pmu name is
'_<digit>'.

For pattern "uncore_imc*", "uncore_imc_0" is parsed ok,
but "uncore_imc_free_running_0" is failed.

Fixes: b2b9d3a3f021 ("perf pmu: Support wildcards on pmu name in dynamic pmu events")
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
tools/perf/util/pmu.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 96f5ff9b5440..9ee123d77e6d 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -3,6 +3,7 @@
#include <linux/compiler.h>
#include <linux/string.h>
#include <linux/zalloc.h>
+#include <linux/ctype.h>
#include <subcmd/pager.h>
#include <sys/types.h>
#include <errno.h>
@@ -741,6 +742,28 @@ struct pmu_events_map *__weak pmu_events_map__find(void)
return perf_pmu__find_map(NULL);
}

+static bool perf_pmu__valid_suffix(char *tok, char *pmu_name)
+{
+ char *p;
+
+ /*
+ * The pmu_name has substring tok. If the format of
+ * pmu_name is tok or tok_digit, return true.
+ */
+ p = pmu_name + strlen(tok);
+ if (*p == 0)
+ return true;
+
+ if (*p != '_')
+ return false;
+
+ ++p;
+ if (*p == 0 || !isdigit(*p))
+ return false;
+
+ return true;
+}
+
bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
{
char *tmp = NULL, *tok, *str;
@@ -769,7 +792,7 @@ bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
*/
for (; tok; name += strlen(tok), tok = strtok_r(NULL, ",", &tmp)) {
name = strstr(name, tok);
- if (!name) {
+ if (!name || !perf_pmu__valid_suffix(tok, (char *)name)) {
res = false;
goto out;
}
@@ -1886,5 +1909,8 @@ int perf_pmu__pattern_match(struct perf_pmu *pmu, char *pattern, char *tok)
if (fnmatch(pattern, name, 0))
return -1;

+ if (!perf_pmu__valid_suffix(tok, name))
+ return -1;
+
return 0;
}
--
2.17.1
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