cpufreq: mediatek: fix KP caused by handler usage after regulator_put/clk_put

[ Upstream commit d51e106240bc755cbe59634b70d567c192b045b2 ]

Any kind of failure in mtk_cpu_dvfs_info_init() will lead to calling
regulator_put() or clk_put() and the KP will occur since the regulator/clk
handlers are used after released in mtk_cpu_dvfs_info_release().

To prevent the usage after regulator_put()/clk_put(), the regulator/clk
handlers are addressed in a way of "Free the Last Thing Style".

Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators")
Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Suggested-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 01d9497..6dc2255 100644 (file)
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -420,7 +420,7 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
                ret = PTR_ERR(info->inter_clk);
                dev_err_probe(cpu_dev, ret,
                              "cpu%d: failed to get intermediate clk\n", cpu);
-               goto out_free_resources;
+               goto out_free_mux_clock;
        }
 
        info->proc_reg = regulator_get_optional(cpu_dev, "proc");
@@ -428,13 +428,13 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
                ret = PTR_ERR(info->proc_reg);
                dev_err_probe(cpu_dev, ret,
                              "cpu%d: failed to get proc regulator\n", cpu);
-               goto out_free_resources;
+               goto out_free_inter_clock;
        }
 
        ret = regulator_enable(info->proc_reg);
        if (ret) {
                dev_warn(cpu_dev, "cpu%d: failed to enable vproc\n", cpu);
-               goto out_free_resources;
+               goto out_free_proc_reg;
        }
 
        /* Both presence and absence of sram regulator are valid cases. */
@@ -442,14 +442,14 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
        if (IS_ERR(info->sram_reg)) {
                ret = PTR_ERR(info->sram_reg);
                if (ret == -EPROBE_DEFER)
-                       goto out_free_resources;
+                       goto out_disable_proc_reg;
 
                info->sram_reg = NULL;
        } else {
                ret = regulator_enable(info->sram_reg);
                if (ret) {
                        dev_warn(cpu_dev, "cpu%d: failed to enable vsram\n", cpu);
-                       goto out_free_resources;
+                       goto out_free_sram_reg;
                }
        }
 
@@ -458,13 +458,13 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
        if (ret) {
                dev_err(cpu_dev,
                        "cpu%d: failed to get OPP-sharing information\n", cpu);
-               goto out_free_resources;
+               goto out_disable_sram_reg;
        }
 
        ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
        if (ret) {
                dev_warn(cpu_dev, "cpu%d: no OPP table\n", cpu);
-               goto out_free_resources;
+               goto out_disable_sram_reg;
        }
 
        ret = clk_prepare_enable(info->cpu_clk);
@@ -533,43 +533,41 @@ out_disable_mux_clock:
 out_free_opp_table:
        dev_pm_opp_of_cpumask_remove_table(&info->cpus);
 
-out_free_resources:
-       if (regulator_is_enabled(info->proc_reg))
-               regulator_disable(info->proc_reg);
-       if (info->sram_reg && regulator_is_enabled(info->sram_reg))
+out_disable_sram_reg:
+       if (info->sram_reg)
                regulator_disable(info->sram_reg);
 
-       if (!IS_ERR(info->proc_reg))
-               regulator_put(info->proc_reg);
-       if (!IS_ERR(info->sram_reg))
+out_free_sram_reg:
+       if (info->sram_reg)
                regulator_put(info->sram_reg);
-       if (!IS_ERR(info->cpu_clk))
-               clk_put(info->cpu_clk);
-       if (!IS_ERR(info->inter_clk))
-               clk_put(info->inter_clk);
+
+out_disable_proc_reg:
+       regulator_disable(info->proc_reg);
+
+out_free_proc_reg:
+       regulator_put(info->proc_reg);
+
+out_free_inter_clock:
+       clk_put(info->inter_clk);
+
+out_free_mux_clock:
+       clk_put(info->cpu_clk);
 
        return ret;
 }
 
 static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
 {
-       if (!IS_ERR(info->proc_reg)) {
-               regulator_disable(info->proc_reg);
-               regulator_put(info->proc_reg);
-       }
-       if (!IS_ERR(info->sram_reg)) {
+       regulator_disable(info->proc_reg);
+       regulator_put(info->proc_reg);
+       if (info->sram_reg) {
                regulator_disable(info->sram_reg);
                regulator_put(info->sram_reg);
        }
-       if (!IS_ERR(info->cpu_clk)) {
-               clk_disable_unprepare(info->cpu_clk);
-               clk_put(info->cpu_clk);
-       }
-       if (!IS_ERR(info->inter_clk)) {
-               clk_disable_unprepare(info->inter_clk);
-               clk_put(info->inter_clk);
-       }
-
+       clk_disable_unprepare(info->cpu_clk);
+       clk_put(info->cpu_clk);
+       clk_disable_unprepare(info->inter_clk);
+       clk_put(info->inter_clk);
        dev_pm_opp_of_cpumask_remove_table(&info->cpus);
        dev_pm_opp_unregister_notifier(info->cpu_dev, &info->opp_nb);
 }