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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0167/1039] cpufreq: qcom-hw: Fix probable nested interrupt handling
Date:   Mon, 24 Jan 2022 19:32:36 +0100
Message-Id: <20220124184130.833736034@linuxfoundation.org>
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From: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>

[ Upstream commit e0e27c3d4e20dab861566f1c348ae44e4b498630 ]

Re-enabling an interrupt from its own interrupt handler may cause
an interrupt storm, if there is a pending interrupt and because its
handling is disabled due to already done entrance into the handler
above in the stack.

Also, apparently it is improper to lock a mutex in an interrupt contex.

Fixes: 275157b367f4 ("cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support")
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cpufreq/qcom-cpufreq-hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index 0138b2ec406dc..35d93361fda1a 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -343,9 +343,9 @@ static irqreturn_t qcom_lmh_dcvs_handle_irq(int irq, void *data)
 
 	/* Disable interrupt and enable polling */
 	disable_irq_nosync(c_data->throttle_irq);
-	qcom_lmh_dcvs_notify(c_data);
+	schedule_delayed_work(&c_data->throttle_work, 0);
 
-	return 0;
+	return IRQ_HANDLED;
 }
 
 static const struct qcom_cpufreq_soc_data qcom_soc_data = {
-- 
2.34.1