[PATCH 2/3] soc: samsung: exynos-pmu: fix use-after-free of interrupt generator node

[Alexey Klimov]

The setup_cpuhp_and_cpuidle() parses the device tree node for the
interrupt generation block via of_parse_phandle() and decrements its
reference count using of_node_put() immediately after fetching the resource
address. However, later the intr_gen_node pointer is passed into
of_syscon_register_regmap().

Fix this by moving the of_node_put() invocation to after the
of_syscon_register_regmap() call, and adding it to correct error paths.

Reported-by: Sashiko <sashiko-bot at kernel.org>
Closes: https://sashiko.dev/#/patchset/20260513-exynos850-cpuhotplug-v4-0-54fec5f65362@linaro.org?part=3
Fixes: 78b72897a5c8 ("soc: samsung: exynos-pmu: Enable CPU Idle for gs101")
Cc: stable at vger.kernel.org
Signed-off-by: Alexey Klimov <alexey.klimov at linaro.org>
---
 drivers/soc/samsung/exynos-pmu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index 6e635872247a..9636287f6794 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c
@@ -428,23 +428,30 @@ static int setup_cpuhp_and_cpuidle(struct device *dev)
 	 * syscon provided regmap.
 	 */
 	ret = of_address_to_resource(intr_gen_node, 0, &intrgen_res);
-	of_node_put(intr_gen_node);
+	if (ret) {
+		of_node_put(intr_gen_node);
+		return ret;
+	}
 
 	virt_addr = devm_ioremap(dev, intrgen_res.start,
 				 resource_size(&intrgen_res));
-	if (!virt_addr)
+	if (!virt_addr) {
+		of_node_put(intr_gen_node);
 		return -ENOMEM;
+	}
 
 	pmu_context->pmuintrgen = devm_regmap_init_mmio(dev, virt_addr,
 							&regmap_pmu_intr);
 	if (IS_ERR(pmu_context->pmuintrgen)) {
 		dev_err(dev, "failed to initialize pmu-intr-gen regmap\n");
+		of_node_put(intr_gen_node);
 		return PTR_ERR(pmu_context->pmuintrgen);
 	}
 
 	/* register custom mmio regmap with syscon */
 	ret = of_syscon_register_regmap(intr_gen_node,
 					pmu_context->pmuintrgen);
+	of_node_put(intr_gen_node);
 	if (ret)
 		return ret;
 

-- 
2.51.0