linux-kernel - [PATCH] PM: runtime: clk: Fix clk_pm_runtime

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Message-ID: <5127441.yGvM1JjtLk@kreacher>
Date:   Thu, 21 May 2020 19:08:09 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Michael Turquette <mturquette@...libre.com>
Subject: [PATCH] PM: runtime: clk: Fix clk_pm_runtime_get() error path

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

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

Index: linux-pm/drivers/clk/clk.c
===================================================================
--- linux-pm.orig/drivers/clk/clk.c
+++ linux-pm/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)