Messages in this thread Patch in this message | | | From | Andrey Smirnov <> | Subject | [PATCH] power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG | Date | Fri, 5 Apr 2019 00:30:20 -0700 |
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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. Change debug prints to use pr_debug insted to resolve the issue.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Cc: Chris Healy <cphealy@gmail.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- drivers/power/supply/power_supply_sysfs.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c index dce24f596160..5e91946731fd 100644 --- a/drivers/power/supply/power_supply_sysfs.c +++ b/drivers/power/supply/power_supply_sysfs.c @@ -383,14 +383,14 @@ int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env) char *prop_buf; char *attrname; - dev_dbg(dev, "uevent\n"); + pr_debug("%s: uevent\n", dev_name(dev)); 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); + pr_debug("%s: POWER_SUPPLY_NAME=%s\n", dev_name(dev), psy->desc->name); ret = add_uevent_var(env, "POWER_SUPPLY_NAME=%s", psy->desc->name); if (ret) @@ -427,7 +427,8 @@ int power_supply_uevent(struct device *dev, struct kobj_uevent_env *env) goto out; } - dev_dbg(dev, "prop %s=%s\n", attrname, prop_buf); + pr_debug("%s: prop %s=%s\n", dev_name(dev), attrname, + prop_buf); ret = add_uevent_var(env, "POWER_SUPPLY_%s=%s", attrname, prop_buf); kfree(attrname); -- 2.20.1
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