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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Hanjun Guo <guohanjun@huawei.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	James Clark <james.clark@arm.com>,
	Leo Yan <leo.yan@linaro.org>,
	linux-acpi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.1 313/473] coresight: etm4x: Fix unbalanced pm_runtime_enable()
Date: Thu,  6 Jun 2024 16:04:02 +0200
Message-ID: <20240606131710.288688254@linuxfoundation.org>
In-Reply-To: <20240606131659.786180261@linuxfoundation.org>
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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anshuman Khandual <anshuman.khandual@arm.com>

[ Upstream commit caa41c47dab7e1054f587e592ab21296e3a6781c ]

There is an unbalanced pm_runtime_enable() in etm4_probe_platform_dev()
when etm4_probe() fails. This problem can be observed via the coresight
etm4 module's (load -> unload -> load) sequence when etm4_probe() fails
in etm4_probe_platform_dev().

[   63.379943] coresight-etm4x 7040000.etm: Unbalanced pm_runtime_enable!
[   63.393630] coresight-etm4x 7140000.etm: Unbalanced pm_runtime_enable!
[   63.407455] coresight-etm4x 7240000.etm: Unbalanced pm_runtime_enable!
[   63.420983] coresight-etm4x 7340000.etm: Unbalanced pm_runtime_enable!
[   63.420999] coresight-etm4x 7440000.etm: Unbalanced pm_runtime_enable!
[   63.441209] coresight-etm4x 7540000.etm: Unbalanced pm_runtime_enable!
[   63.454689] coresight-etm4x 7640000.etm: Unbalanced pm_runtime_enable!
[   63.474982] coresight-etm4x 7740000.etm: Unbalanced pm_runtime_enable!

This fixes the above problem - with an explicit pm_runtime_disable() call
when etm4_probe() fails during etm4_probe_platform_dev().

Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: coresight@lists.linaro.org
Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices")
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240314055843.2625883-2-anshuman.khandual@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index fda48a0afc1a5..63fe506a60314 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2053,6 +2053,9 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
 	ret = etm4_probe(&pdev->dev, NULL, 0);
 
 	pm_runtime_put(&pdev->dev);
+	if (ret)
+		pm_runtime_disable(&pdev->dev);
+
 	return ret;
 }
 
-- 
2.43.0