linux-kernel - [PATCH AUTOSEL 4.9 7/9] power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY

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Message-Id: <20190516114134.9146-7-sashal@kernel.org>
Date:   Thu, 16 May 2019 07:41:31 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Chris Healy <cphealy@...il.com>, linux-pm@...r.kernel.org,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 7/9] power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG

From: Andrey Smirnov <andrew.smirnov@...il.com>

[ Upstream commit 349ced9984ff540ce74ca8a0b2e9b03dc434b9dd ]

Fix a similar endless event loop as was done in commit
8dcf32175b4e ("i2c: prevent endless uevent loop with
CONFIG_I2C_DEBUG_CORE"):

  The culprit is the dev_dbg printk in the i2c uevent handler. If
  this is activated (for instance by CONFIG_I2C_DEBUG_CORE) it results
  in an endless loop with systemd-journald.

  This happens if user-space scans the system log and reads the uevent
  file to get information about a newly created device, which seems
  fair use to me. Unfortunately reading the "uevent" file uses the
  same function that runs for creating the uevent for a new device,
  generating the next syslog entry

Both CONFIG_I2C_DEBUG_CORE and CONFIG_POWER_SUPPLY_DEBUG were reported
in https://bugs.freedesktop.org/show_bug.cgi?id=76886 but only former
seems to have been fixed. Drop debug prints as it was done in I2C
subsystem to resolve the issue.

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Cc: Chris Healy <cphealy@...il.com>
Cc: linux-pm@...r.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/power/supply/power_supply_sysfs.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index bcde8d13476af..c0fc98e03c912 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -278,15 +278,11 @@ int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env)
 	char *prop_buf;
 	char *attrname;
 
-	dev_dbg(dev, "uevent\n");
-
 	if (!psy || !psy->desc) {
 		dev_dbg(dev, "No power supply yet\n");
 		return ret;
 	}
 
-	dev_dbg(dev, "POWER_SUPPLY_NAME=%s\n", psy->desc->name);
-
 	ret = add_uevent_var(env, "POWER_SUPPLY_NAME=%s", psy->desc->name);
 	if (ret)
 		return ret;
@@ -322,8 +318,6 @@ int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env)
 			goto out;
 		}
 
-		dev_dbg(dev, "prop %s=%s\n", attrname, prop_buf);
-
 		ret = add_uevent_var(env, "POWER_SUPPLY_%s=%s", attrname, prop_buf);
 		kfree(attrname);
 		if (ret)
-- 
2.20.1