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From fced531b7c7e18192e7982637c8e8f20c29aad64 Mon Sep 17 00:00:00 2001
From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
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 <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>
---
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);
}
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