[PATCH 5.0 120/139] power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG

Greg Kroah-Hartman
2019-05-23T19:37:19Z

[ 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@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.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 dce24f5961609..5358a80d854f9 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -383,15 +383,11 @@ 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;
@@ -427,8 +423,6 @@ 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