power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG [Linux 5.1]

power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG [Linux 5.1]

This Linux kernel change "power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG" is included in the Linux 5.1 release. This change is authored by Andrey Smirnov <andrew.smirnov [at] gmail.com> on Wed Apr 24 00:16:10 2019 -0700. The commit for this change in Linux stable tree is 349ced9 (patch).

power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG

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>

There are 6 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 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 dce24f5..5358a80 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)

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