linux-kernel - [PATCH 5.7 088/163] PM: runtime: clk: Fix clk_pm_runtime

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Date:   Tue, 16 Jun 2020 17:34:22 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 5.7 088/163] PM: runtime: clk: Fix clk_pm_runtime_get() error path

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

commit 64c7d7ea22d86cacb65d0c097cc447bc0e6d8abd upstream.

clk_pm_runtime_get() assumes that the PM-runtime usage counter will
be dropped by pm_runtime_get_sync() on errors, which is not the case,
so PM-runtime references to devices acquired by the former are leaked
on errors returned by the latter.

Fix this by modifying clk_pm_runtime_get() to drop the reference if
pm_runtime_get_sync() returns an error.

Fixes: 9a34b45397e5 clk: Add support for runtime PM
Cc: 4.15+ <stable@...r.kernel.org> # 4.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/clk/clk.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -114,7 +114,11 @@ static int clk_pm_runtime_get(struct clk
 		return 0;

 	ret = pm_runtime_get_sync(core->dev);
-	return ret < 0 ? ret : 0;
+	if (ret < 0) {
+		pm_runtime_put_noidle(core->dev);
+		return ret;
+	}
+	return 0;
 }

 static void clk_pm_runtime_put(struct clk_core *core)