nvmed: Fix nvme worker thread deadlock The issue was nvme worker can be destroyed on it's own thread which will make a deadlock saying it is waiting for itself in the destructor of the NVMeMiWorker. We have such case because we are passing sharedPtr of nvmeMi object which is the owner of worker. While the nvmeMi object is deleted from the main thread (remove entry from deviceMap) but worker is still running the job where the shared ptr of nvme mi has already passed. Now nvme mi will try to be destroyed in the worker thread which means worker thread will also be destroyed there and will create deadlock since the destructor is waiting for the thread to be done and the thread is waiting for the destructor to be done. To resolve this, we need to make sure the destruction is happening in main thread. Created sharedPtr of worker with custom deleter which will make sure the final destruction is happening in the main thread. Also made sure this is the only way of creating NVMeMiWorker. Tested: Send interface removed signal continuously and in parallel make dbus query to host initiated telemetry log. Detailed script can be found in b/438827535#comment17. Did not see any resource deadlock. Google-Bug-Id: 438827535 Change-Id: I4b42e9647a1673c1da2f73b89981b50e570a9523 Signed-off-by: Munawar Hussain <munawarhussain@google.com>
dbus-sensors is a collection of sensor applications that provide the xyz.openbmc_project.Sensor collection of interfaces. They read sensor values from hwmon, d-bus, or direct driver access to provide readings. Some advance non-sensor features such as fan presence, pwm control, and automatic cpu detection (x86) are also supported.
runtime re-configurable from d-bus (entity-manager or the like)
isolated: each sensor type is isolated into its own daemon, so a bug in one sensor is unlikely to affect another, and single sensor modifications are possible
async single-threaded: uses sdbusplus/asio bindings
multiple data inputs: hwmon, d-bus, direct driver access
A typical dbus-sensors object support the following dbus interfaces:
Path /xyz/openbmc_project/sensors/<type>/<sensor_name>
Interfaces xyz.openbmc_project.Sensor.Value
xyz.openbmc_project.Sensor.Threshold.Critical
xyz.openbmc_project.Sensor.Threshold.Warning
xyz.openbmc_project.State.Decorator.Availability
xyz.openbmc_project.State.Decorator.OperationalStatus
xyz.openbmc_project.Association.Definitions
Sensor interfaces collection are described here.
Consumer examples of these interfaces are Redfish, Phosphor-Pid-Control, IPMI SDR.
dbus-sensor daemons are reactors that dynamically create and update sensors configuration when system configuration gets updated.
Using asio timers and async calls, dbus-sensor daemons read sensor values and check thresholds periodically. PropertiesChanged signals will be broadcasted for other services to consume when value or threshold status change. OperationStatus is set to false if the sensor is determined to be faulty.
A simple sensor example can be found here.
Sensor devices are described using Exposes records in configuration file. Name and Type fields are required. Different sensor types have different fields. Refer to entity manager schema for complete list.