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Wysocki" , Viresh Kumar , Matthias Brugger , AngeloGioacchino Del Regno , Kevin Hilman , Rex-BC Chen , Jia-Wei Chang CC: , , , , , Nick Hainke , Dan Carpenter Subject: [PATCH v2 2/4] cpufreq: mediatek: fix KP caused by handler usage after regulator_put/clk_put Date: Fri, 24 Mar 2023 18:11:28 +0800 Message-ID: <20230324101130.14053-3-jia-wei.chang@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20230324101130.14053-1-jia-wei.chang@mediatek.com> References: <20230324101130.14053-1-jia-wei.chang@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230324_031151_759063_01549C65 X-CRM114-Status: GOOD ( 13.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: "Jia-Wei Chang" 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 Link: https://lore.kernel.org/linux-arm-kernel/20220921071913.p7kwsjnnuad2jgvk@vireshk-i7/T/ Suggested-by: Dan Carpenter Link: https://lore.kernel.org/lkml/67024b47-f3c9-4764-9883-d52602cfefca@kili.mountain/ --- drivers/cpufreq/mediatek-cpufreq.c | 62 +++++++++++++++--------------- 1 file changed, 30 insertions(+), 32 deletions(-) diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c index 01d949707c37..6dc225546a8d 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); }