perf test sample-parsing: Validate PERF_FORMAT_GROUP values without LOST

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The sample parsing test only validates grouped read values when
PERF_FORMAT_LOST is present.

For PERF_FORMAT_GROUP without PERF_FORMAT_LOST, the contents of
read.group.values[] are not validated, allowing corruption of the parsed
value and id fields to go undetected.

The values are also handed to the synthesis as a plain array of struct
sample_read_value, which always has a 24-byte stride, while
read.group.values is expected to be packed according to read_format --
evsel__parse_sample() points it into the event data.  Without
PERF_FORMAT_LOST the stride is 16, so both the synthesis and the
comparison walk overlapping bytes and the test passes regardless of the
contents.

Validate value and id for grouped reads and continue to validate lost
when PERF_FORMAT_LOST is present, walking the entries with
next_sample_read_value().  Also build the input packed using
sample_read_value_size() so the compared fields are the real ones.

Verified with a deliberate stride bug in copy_read_group_values(): the
test still passes without this change and fails at read_format 0xc with
it applied.

Signed-off-by: PVS Narasimha Rao <venkatasuryapala@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

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PVS Narasimha Rao 2026-08-10 11:49:25 +05:30 • committed by Namhyung Kim

parent 62972e5644

commit 6ae6fb96cc

1 changed files with 34 additions and 5 deletions

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tools/perf/tests/sample-parsing.c

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