Commit d51e1062 authored by Jia-Wei Chang's avatar Jia-Wei Chang Committed by Viresh Kumar
Browse files

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: default avatarJia-Wei Chang <jia-wei.chang@mediatek.com>
Fixes: 4b9ceb75 ("cpufreq: mediatek: Enable clocks and regulators")
Suggested-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Suggested-by: default avatarDan Carpenter <error27@gmail.com>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent d51c6323

drivers/cpufreq/mediatek-cpufreq.c

+30 −32
Original line number Diff line number Diff line
@@ -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 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu) 
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))



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)) {

	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);

	}



	dev_pm_opp_of_cpumask_remove_table(&info->cpus);

	dev_pm_opp_unregister_notifier(info->cpu_dev, &info->opp_nb);

}