[ Upstream commit 89aaeaf842 ]
The pyrf_event__new() method copies the event obtained from the perf
ring buffer to a structure that will then be turned into a python object
for further consumption, so it copies perf_event.header.size bytes to
its 'event' member:
$ pahole -C pyrf_event /tmp/build/perf-tools-next/python/perf.cpython-312-x86_64-linux-gnu.so
struct pyrf_event {
PyObject ob_base; /* 0 16 */
struct evsel * evsel; /* 16 8 */
struct perf_sample sample; /* 24 312 */
/* XXX last struct has 7 bytes of padding, 2 holes */
/* --- cacheline 5 boundary (320 bytes) was 16 bytes ago --- */
union perf_event event; /* 336 4168 */
/* size: 4504, cachelines: 71, members: 4 */
/* member types with holes: 1, total: 2 */
/* paddings: 1, sum paddings: 7 */
/* last cacheline: 24 bytes */
};
$
It was doing so without checking if the event just obtained has more
than that space, fix it.
This isn't a proper, final solution, as we need to support larger
events, but for the time being we at least bounds check and document it.
Fixes: 877108e42b ("perf tools: Initial python binding")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250312203141.285263-7-acme@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ccf40f8263