Patch "cpufreq: mediatek: fix KP caused by handler usage after regulator_put/clk_put" has been added to the 6.1-stable tree

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This is a note to let you know that I've just added the patch titled

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

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cpufreq-mediatek-fix-kp-caused-by-handler-usage-afte.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 0786fea46a385d1b050cffe32ef365d730556275
Author: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>
Date:   Fri Mar 24 18:11:28 2023 +0800

    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@xxxxxxxxxxxx>
    Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators")
    Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
    Suggested-by: Dan Carpenter <error27@xxxxxxxxx>
    Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 01d949707c373..6dc225546a8d6 100644
--- 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 @@ 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))
-		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);
 }



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