perf: arm_spe: handle devm_kasprintf() failure

devm_kasprintf() may return NULL on failure of internal allocation
thus the assignment to 'name' is not safe if unchecked. If NULL
is passed in for name then perf_pmu_register() would not fail
but rather silently jump to skip_type which is not the intent
here. As perf_pmu_register() may also return -ENOMEM returning
-ENOMEM in the (unlikely) failure case of devm_kasprintf() should
be fine here as well.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Fixes: d5d9696b03 ("drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
[will: reworded error message]
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/perf/arm_spe_pmu.c

@@ -927,6 +927,11 @@ static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
 
 	idx = atomic_inc_return(&pmu_idx);
 	name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
+	if (!name) {
+		dev_err(dev, "failed to allocate name for pmu %d\n", idx);
+		return -ENOMEM;
+	}
+
 	return perf_pmu_register(&spe_pmu->pmu, name, -1);
 }