linux-kernel - [PATCH] PM: Fix dev_pm_put_subsys_data() to not call kfree() while holding device power lock

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Date:	Fri, 3 May 2013 20:46:50 +0000
From:	Shuah Khan <shuah.kh@...sung.com>
To:	"len.brown@...el.com" <len.brown@...el.com>,
	"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
	"pavel@....cz" <pavel@....cz>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"shuahkhan@...il.com" <shuahkhan@...il.com>
Subject: [PATCH] PM: Fix dev_pm_put_subsys_data() to not call kfree() while
 holding device power lock

dev_pm_put_subsys_data() calls kfree() while holding device power lock, when
the reference count is 0. Fix it to call kfree() after releasing the lock.

Signed-off-by: Shuah Khan <shuah.kh@...sung.com>
---
 drivers/base/power/common.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index 39c3252..da05fe2 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -73,13 +73,17 @@ int dev_pm_put_subsys_data(struct device *dev)
 
 	if (--psd->refcount == 0) {
 		dev->power.subsys_data = NULL;
-		kfree(psd);
 		ret = 1;
 	}
 
  out:
 	spin_unlock_irq(&dev->power.lock);
 
+	if (ret == 1) {
+		/* kfree() verifies that its argument is nonzero. */
+		kfree(psd);
+	}
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
-- 
1.7.10.4