Commit 277ce1ef authored Feb 28, 2020 by Kan Liang Committed by Arnaldo Carvalho de Melo Mar 09, 2020

perf header: Add check for unexpected use of reserved membrs in event attr



The perf.data may be generated by a newer version of perf tool, which
support new input bits in attr, e.g. new bit for branch_sample_type.

The perf.data may be parsed by an older version of perf tool later.  The
old perf tool may parse the perf.data incorrectly. There is no warning
message for this case.

Current perf header never check for unknown input bits in attr.

When read the event desc from header, check the stored event attr.  The
reserved bits, sample type, read format and branch sample type will be
checked.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pavel Gerasimov <pavel.gerasimov@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Link: http://lkml.kernel.org/r/20200228163011.19358-4-kan.liang@linux.intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent d3f85437

tools/perf/util/header.c

+37 −0

Original line number	Diff line number	Diff line
		@@ -1590,6 +1590,40 @@ static void free_event_desc(struct evsel *events)
		free(events);
		}

		static bool perf_attr_check(struct perf_event_attr *attr)
		{
		if (attr->__reserved_1 \|\| attr->__reserved_2 \|\| attr->__reserved_3) {
		pr_warning("Reserved bits are set unexpectedly. "
		"Please update perf tool.\n");
		return false;
		}

		if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) {
		pr_warning("Unknown sample type (0x%llx) is detected. "
		"Please update perf tool.\n",
		attr->sample_type);
		return false;
		}

		if (attr->read_format & ~(PERF_FORMAT_MAX-1)) {
		pr_warning("Unknown read format (0x%llx) is detected. "
		"Please update perf tool.\n",
		attr->read_format);
		return false;
		}

		if ((attr->sample_type & PERF_SAMPLE_BRANCH_STACK) &&
		(attr->branch_sample_type & ~(PERF_SAMPLE_BRANCH_MAX-1))) {
		pr_warning("Unknown branch sample type (0x%llx) is detected. "
		"Please update perf tool.\n",
		attr->branch_sample_type);

		return false;
		}

		return true;
		}

		static struct evsel read_event_desc(struct feat_fd ff)
		{
		struct evsel evsel, events = NULL;
		@@ -1634,6 +1668,9 @@ static struct evsel read_event_desc(struct feat_fd ff)

		memcpy(&evsel->core.attr, buf, msz);

		if (!perf_attr_check(&evsel->core.attr))
		goto error;

		if (do_read_u32(ff, &nr))
		goto error;

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