s390/perf: Return error when debug_register fails

BugLink: https://bugs.launchpad.net/bugs/1854855

[ Upstream commit ec0c0bb4 ]

Return an error when the function debug_register() fails allocating
the debug handle.
Also remove the registered debug handle when the initialization fails
later on.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/s390/kernel/perf_cpum_sf.c

@@ -1616,14 +1616,17 @@ static int __init init_cpum_sampling_pmu(void)
 	}
 
 	sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80);
-	if (!sfdbg)
+	if (!sfdbg) {
 		pr_err("Registering for s390dbf failed\n");
+		return -ENOMEM;
+	}
 	debug_register_view(sfdbg, &debug_sprintf_view);
 
 	err = register_external_irq(EXT_IRQ_MEASURE_ALERT,
 				    cpumf_measurement_alert);
 	if (err) {
 		pr_cpumsf_err(RS_INIT_FAILURE_ALRT);
+		debug_unregister(sfdbg);
 		goto out;
 	}
 
@@ -1632,6 +1635,7 @@ static int __init init_cpum_sampling_pmu(void)
 		pr_cpumsf_err(RS_INIT_FAILURE_PERF);
 		unregister_external_irq(EXT_IRQ_MEASURE_ALERT,
 					cpumf_measurement_alert);
+		debug_unregister(sfdbg);
 		goto out;
 	}
 	perf_cpu_notifier(cpumf_pmu_notifier);