linux-kernel - [PATCH v2 08/24] perf: Cleanup perf_try_init

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Message-ID: <20250205102449.110145835@infradead.org>
Date: Wed, 05 Feb 2025 11:21:28 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: mingo@...nel.org,
 ravi.bangoria@....com,
 lucas.demarchi@...el.com
Cc: linux-kernel@...r.kernel.org,
 peterz@...radead.org,
 willy@...radead.org,
 acme@...nel.org,
 namhyung@...nel.org,
 mark.rutland@....com,
 alexander.shishkin@...ux.intel.com,
 jolsa@...nel.org,
 irogers@...gle.com,
 adrian.hunter@...el.com,
 kan.liang@...ux.intel.com
Subject: [PATCH v2 08/24] perf: Cleanup perf_try_init_event()

Make sure that perf_try_init_event() doesn't leave event->pmu nor
event->destroy set on failure.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |   69 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 28 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -12019,38 +12019,51 @@ static int perf_try_init_event(struct pm
 	if (ctx)
 		perf_event_ctx_unlock(event->group_leader, ctx);
 
-	if (!ret) {
-		if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
-		    has_extended_regs(event))
-			ret = -EOPNOTSUPP;
-
-		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
-		    event_has_any_exclude_flag(event))
-			ret = -EINVAL;
-
-		if (pmu->scope != PERF_PMU_SCOPE_NONE && event->cpu >= 0) {
-			const struct cpumask *cpumask = perf_scope_cpu_topology_cpumask(pmu->scope, event->cpu);
-			struct cpumask *pmu_cpumask = perf_scope_cpumask(pmu->scope);
-			int cpu;
-
-			if (pmu_cpumask && cpumask) {
-				cpu = cpumask_any_and(pmu_cpumask, cpumask);
-				if (cpu >= nr_cpu_ids)
-					ret = -ENODEV;
-				else
-					event->event_caps |= PERF_EV_CAP_READ_SCOPE;
-			} else {
-				ret = -ENODEV;
-			}
-		}
+	if (ret)
+		goto err_pmu;
 
-		if (ret && event->destroy)
-			event->destroy(event);
+	if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
+	    has_extended_regs(event)) {
+		ret = -EOPNOTSUPP;
+		goto err_destroy;
 	}
 
-	if (ret)
-		module_put(pmu->module);
+	if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
+	    event_has_any_exclude_flag(event)) {
+		ret = -EINVAL;
+		goto err_destroy;
+	}
+
+	if (pmu->scope != PERF_PMU_SCOPE_NONE && event->cpu >= 0) {
+		const struct cpumask *cpumask;
+		struct cpumask *pmu_cpumask;
+		int cpu;
+
+		cpumask = perf_scope_cpu_topology_cpumask(pmu->scope, event->cpu);
+		pmu_cpumask = perf_scope_cpumask(pmu->scope);
+
+		ret = -ENODEV;
+		if (!pmu_cpumask || !cpumask)
+			goto err_destroy;
+
+		cpu = cpumask_any_and(pmu_cpumask, cpumask);
+		if (cpu >= nr_cpu_ids)
+			goto err_destroy;
+
+		event->event_caps |= PERF_EV_CAP_READ_SCOPE;
+	}
+
+	return 0;
+
+err_destroy:
+	if (event->destroy) {
+		event->destroy(event);
+		event->destroy = NULL;
+	}
 
+err_pmu:
+	event->pmu = NULL;
+	module_put(pmu->module);
 	return ret;
 }