perf arm-spe: Reject zero nr_cpu in metadata to prevent division by zero
arm_spe__alloc_metadata() reads nr_cpu from the auxtrace_info priv array without validation. When a crafted perf.data provides nr_cpu=0, the per_cpu_sz calculation divides by zero: per_cpu_sz = (metadata_size - (hdr_sz * sizeof(u64))) / (*nr_cpu); Reject nr_cpu <= 0 early, before the division. The caller already treats NULL return with metadata_ver != 1 as a parse failure. Fixes: 7842a4b6ff698 ("perf arm-spe: Support metadata version 2") Reported-by: sashiko-bot <sashiko-bot@kernel.org> Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Reviewed-by: James Clark <james.clark@linaro.org> Reviewed-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org>