linux-kernel - [BACKPORT 4.14.y v3 3/3] power: supply: sysfs: ratelimit property read error message

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Message-Id: <c136c30f8b113ba9b0359f57d2a109766c1d7a70.1569405445.git.baolin.wang@linaro.org>
Date:   Wed, 25 Sep 2019 18:03:35 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     stable@...r.kernel.org, sre@...nel.org
Cc:     david@...hnology.com, linux-pm@...r.kernel.org, arnd@...db.de,
        baolin.wang@...aro.org, orsonzhai@...il.com,
        vincent.guittot@...aro.org, linux-kernel@...r.kernel.org
Subject: [BACKPORT 4.14.y v3 3/3] power: supply: sysfs: ratelimit property read error message

From: David Lechner <david@...hnology.com>

[Upstream commit 87a2b65fc855e6be50f791c2ebbb492541896827]

This adds rate limiting to the message that is printed when reading a
power supply property via sysfs returns an error. This will prevent
userspace applications from unintentionally dDOSing the system by
continuously reading a property that returns an error.

Signed-off-by: David Lechner <david@...hnology.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
---
 drivers/power/supply/power_supply_sysfs.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index eb5dc74..2ccaf4f 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -91,7 +91,8 @@ static ssize_t power_supply_show_property(struct device *dev,
 				dev_dbg(dev, "driver has no data for `%s' property\n",
 					attr->attr.name);
 			else if (ret != -ENODEV && ret != -EAGAIN)
-				dev_err(dev, "driver failed to report `%s' property: %zd\n",
+				dev_err_ratelimited(dev,
+					"driver failed to report `%s' property: %zd\n",
 					attr->attr.name, ret);
 			return ret;
 		}
-- 
1.7.9.5