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Wysocki" , Viresh Kumar , Matthias Brugger , AngeloGioacchino Del Regno , Kevin Hilman , Rex-BC Chen , Jia-Wei Chang CC: , , , , , Nick , Dan Carpenter Subject: [PATCH v1 2/3] cpufreq: mediatek: fix KP caused by handler usage after regulator_put/clk_put Date: Fri, 10 Mar 2023 13:17:49 +0800 Message-ID: <20230310051750.4745-3-jia-wei.chang@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20230310051750.4745-1-jia-wei.chang@mediatek.com> References: <20230310051750.4745-1-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-20230309_211846_900202_1E32B429 X-CRM114-Status: GOOD ( 12.80 ) 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 reassigned to NULL value for validation check afterwards. Signed-off-by: Jia-Wei Chang Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators") Reported-by: AngeloGioacchino Del Regno Link: https://lore.kernel.org/linux-arm-kernel/20220921071913.p7kwsjnnuad2jgvk@vireshk-i7/T/ Reviewed-by: AngeloGioacchino Del Regno --- drivers/cpufreq/mediatek-cpufreq.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c index 01d949707c37..cb8b76f9c2c3 100644 --- a/drivers/cpufreq/mediatek-cpufreq.c +++ b/drivers/cpufreq/mediatek-cpufreq.c @@ -539,35 +539,47 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu) if (info->sram_reg && regulator_is_enabled(info->sram_reg)) regulator_disable(info->sram_reg); - if (!IS_ERR(info->proc_reg)) + if (!IS_ERR(info->proc_reg)) { regulator_put(info->proc_reg); - if (!IS_ERR(info->sram_reg)) + info->proc_reg = NULL; + } + if (!IS_ERR(info->sram_reg)) { regulator_put(info->sram_reg); - if (!IS_ERR(info->cpu_clk)) + info->sram_reg = NULL; + } + if (!IS_ERR(info->cpu_clk)) { clk_put(info->cpu_clk); - if (!IS_ERR(info->inter_clk)) + info->cpu_clk = NULL; + } + if (!IS_ERR(info->inter_clk)) { clk_put(info->inter_clk); + info->inter_clk = NULL; + } return ret; } static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info) { - if (!IS_ERR(info->proc_reg)) { + if (!IS_ERR_OR_NULL(info->proc_reg)) { regulator_disable(info->proc_reg); regulator_put(info->proc_reg); + info->proc_reg = NULL; } - if (!IS_ERR(info->sram_reg)) { + if (!IS_ERR_OR_NULL(info->sram_reg)) { regulator_disable(info->sram_reg); regulator_put(info->sram_reg); + info->sram_reg = NULL; } - if (!IS_ERR(info->cpu_clk)) { + if (!IS_ERR_OR_NULL(info->cpu_clk)) { clk_disable_unprepare(info->cpu_clk); clk_put(info->cpu_clk); + info->cpu_clk = NULL; } - if (!IS_ERR(info->inter_clk)) { + if (!IS_ERR_OR_NULL(info->inter_clk)) { clk_disable_unprepare(info->inter_clk); clk_put(info->inter_clk); + info->inter_clk = NULL; } dev_pm_opp_of_cpumask_remove_table(&info->cpus);