From fced531b7c7e18192e7982637c8e8f20c29aad64 Mon Sep 17 00:00:00 2001 From: Jia-Wei Chang Date: Fri, 24 Mar 2023 18:11:28 +0800 Subject: [PATCH 18/21] cpufreq: mediatek: fix KP caused by handler usage after regulator_put/clk_put 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 Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators") Suggested-by: AngeloGioacchino Del Regno Suggested-by: Dan Carpenter Signed-off-by: Viresh Kumar --- drivers/cpufreq/mediatek-cpufreq.c | 62 +++++++++++++++--------------- 1 file changed, 30 insertions(+), 32 deletions(-) --- a/drivers/cpufreq/mediatek-cpufreq.c +++ b/drivers/cpufreq/mediatek-cpufreq.c @@ -420,7 +420,7 @@ static int mtk_cpu_dvfs_info_init(struct 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 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 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 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); }