hwmon_pmu__for_each_event() formats description strings via:
len = snprintf(desc_buf, sizeof(desc_buf), "%s in unit %s named %s.", ...);
len += hwmon_pmu__describe_items(hwm, desc_buf + len, sizeof(desc_buf) - len, ...);
If value->label is long enough to cause snprintf() to truncate, it
returns the would-have-been-written count, making len exceed
sizeof(desc_buf). The subsequent sizeof(desc_buf) - len underflows
to a huge size_t value, disabling bounds checking in
hwmon_pmu__describe_items().
The alias_buf snprintf has the same issue. Switch both to scnprintf()
which returns actual bytes written.
Fixes: 53cc0b351e ("perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ae75956c16