[PATCH v9 01/20] RISC-V: perf: fix resource cleanup on driver probe failure

[Atish Patra <atish.patra@linux.dev>]

From: Atish Patra <atishp@meta.com>

Sashiko pointed out various UAF and memory leak issues around
pmu_sbi_device_probe() error paths.

If the probe fails, here are list of cleanups needed.
a. Already registered pmu must be freed
b. per cpu IRQ must be released
c. pmu_ctr_list data structure must be freed
d. cpu hotplug state must be cleaned up only if added.

Fix the resource cleanup by reorganizing the code around probe failure.

Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Link: https://patch.msgid.link/20260701-counter_delegation-v8-1-7909f863a645@meta.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Reviewed-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Signed-off-by: Atish Patra <atishp@meta.com>
---
 drivers/perf/riscv_pmu_sbi.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index dfc886dee5ad..50220f7b46d9 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1219,22 +1219,29 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
 					  DOMAIN_BUS_ANY);
 	if (!domain) {
 		pr_err("Failed to find INTC IRQ root domain\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto err;
 	}
 
 	riscv_pmu_irq = irq_create_mapping(domain, riscv_pmu_irq_num);
 	if (!riscv_pmu_irq) {
 		pr_err("Failed to map PMU interrupt for node\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto err;
 	}
 
 	ret = request_percpu_irq(riscv_pmu_irq, pmu_sbi_ovf_handler, "riscv-pmu", hw_events);
 	if (ret) {
 		pr_err("registering percpu irq failed [%d]\n", ret);
-		return ret;
+		irq_dispose_mapping(riscv_pmu_irq);
+		riscv_pmu_irq = 0;
+		goto err;
 	}
 
 	return 0;
+err:
+	riscv_pmu_use_irq = false;
+	return ret;
 }
 
 #ifdef CONFIG_CPU_PM
@@ -1301,7 +1308,8 @@ static void riscv_pmu_destroy(struct riscv_pmu *pmu)
 		}
 	}
 	riscv_pm_pmu_unregister(pmu);
-	cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+	if (!hlist_unhashed(&pmu->node))
+		cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
 }
 
 static void pmu_sbi_event_init(struct perf_event *event)
@@ -1423,6 +1431,7 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 	struct riscv_pmu *pmu = NULL;
 	int ret = -ENODEV;
 	int num_counters;
+	bool irq_requested = false;
 
 	pr_info("SBI PMU extension is available\n");
 	pmu = riscv_pmu_alloc();
@@ -1451,6 +1460,7 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_EXCLUDE;
 	}
+	irq_requested = (ret == 0);
 
 	pmu->pmu.attr_groups = riscv_pmu_attr_groups;
 	pmu->pmu.parent = &pdev->dev;
@@ -1469,11 +1479,11 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 
 	ret = riscv_pm_pmu_register(pmu);
 	if (ret)
-		goto out_unregister;
+		goto out_destroy;
 
 	ret = perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
 	if (ret)
-		goto out_unregister;
+		goto out_destroy;
 
 	/* SBI PMU Snapsphot is only available in SBI v2.0 */
 	if (sbi_v2_available) {
@@ -1514,9 +1524,20 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 	return 0;
 
 out_unregister:
+	perf_pmu_unregister(&pmu->pmu);
+
+out_destroy:
 	riscv_pmu_destroy(pmu);
+	if (irq_requested) {
+		free_percpu_irq(riscv_pmu_irq, pmu->hw_events);
+		irq_dispose_mapping(riscv_pmu_irq);
+		riscv_pmu_irq = 0;
+	}
 
 out_free:
+	free_percpu(pmu->hw_events);
+	kfree(pmu_ctr_list);
+	pmu_ctr_list = NULL;
 	kfree(pmu);
 	return ret;
 }

-- 
2.53.0-Meta