linux-kernel - [PATCH v3 2/8] PM / Domains: Handle safely genpd_syscore

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Message-Id: <20170628145623.20716-3-krzk@kernel.org>
Date:   Wed, 28 Jun 2017 16:56:17 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Krzysztof Kozlowski <krzk@...nel.org>
Subject: [PATCH v3 2/8] PM / Domains: Handle safely genpd_syscore_switch() call on non-genpd device

genpd_syscore_switch() had two problems:
1. It silently assumed that device, it is being called for, belongs to
   generic power domain and used container_of() on its power domain
   pointer.  Such assumption might not be true always.

2. It iterated over list of generic power domains without holding
   gpd_list_lock mutex thus list could have been modified in the same
   time.

Usage of genpd_lookup_dev() solves both problems as it is safe a call
for non-generic power domains and uses mutex when iterating.

Reported-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Acked-by: Ulf Hansson <ulf.hansson@...aro.org>

---

Not tested on real hardware.
---
 drivers/base/power/domain.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 01e31d9f6c94..d31a4434b8b3 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1098,8 +1098,8 @@ static void genpd_syscore_switch(struct device *dev, bool suspend)
 {
 	struct generic_pm_domain *genpd;
 
-	genpd = dev_to_genpd(dev);
-	if (!pm_genpd_present(genpd))
+	genpd = genpd_lookup_dev(dev);
+	if (!genpd)
 		return;
 
 	if (suspend) {
-- 
2.11.0