ACRN-Crashlog

Introduction

ACRN-Crashlog is a collective name for various tools (acrnprobe, usercrash_s, usercrash_c, debugger, and more) and a overall control utility called crashlogctl. Together these tools collect logs and information after each crash or event on an ACRN platform, including the hypervisor, Service OS (SOS), and Android as a Guest (AaaG). ACRN-Crashlog provides a flexible way to configure which events are of interest, by using an XML configuration file.

Building

Build dependencies

The ACRN-Crashlog tool depends on the following libraries (build and runtime):

  • libevent
  • OpenSSL
  • libxml2
  • systemd
  • telemetrics-client-dev (optional, detected at build time)
  • libblkid
  • e2fsprogs

Refer to the Try using ACRN for instructions on how to set-up your build environment, and follow the instructions below to build and configure the ACRN-Crashlog tool.

Build

To build the ACRN-Crashlog, run:

$ cd acrn-crashlog
$ make

To remove all generated files and return the folder to its clean state, use:

$ cd acrn-crashlog
$ make clean

Installing

To install the build:

$ cd acrn-crashlog
$ sudo make install

Enabling/Disabling

To enable this tool:

$ sudo crashlogctl enable

Then it will show:

... Backup core pattern to /var/log/crashlog/default_core_pattern
'/usr/share/defaults/telemetrics/telemetrics.conf' ->
'/etc/telemetrics/telemetrics.conf'
... Set server_delivery_enabled=false in /etc/telemetrics/telemetrics.conf
... Set record_retention_enabled=true in /etc/telemetrics/telemetrics.conf
'/usr/share/acrn/crashlog/40-watchdog.conf' ->
'/etc/systemd/system.conf.d/40-watchdog.conf'
'/usr/share/acrn/crashlog/80-coredump.conf' ->
'/etc/sysctl.d/80-coredump.conf'
Created symlink /etc/systemd/system/hprobe.timer -> /dev/null.
Created symlink /etc/systemd/system/telemd-update-trigger.service -> /dev/null.
Created symlink /etc/systemd/system/pstore-clean.service -> /dev/null.
Created symlink /etc/systemd/system/pstore-probe.service -> /dev/null.
Created symlink /etc/systemd/system/oops-probe.service -> /dev/null.
Created symlink /etc/systemd/system/klogscanner.service -> /dev/null.
Created symlink /etc/systemd/system/journal-probe.service -> /dev/null.
Created symlink /etc/systemd/system/bert-probe.service -> /dev/null.
Created symlink /etc/systemd/system/multi-user.target.wants/acrnprobe.service -> /usr/lib/systemd/system/acrnprobe.service.
Created symlink /etc/systemd/system/multi-user.target.wants/usercrash.service -> /usr/lib/systemd/system/usercrash.service.
*** Please reboot your system. ***

Follow the hints to reboot the system:

$ sudo reboot

To disable this tool:

$ sudo crashlogctl disable

Then it will show:

Removed /etc/systemd/system/multi-user.target.wants/acrnprobe.service.
Removed /etc/systemd/system/multi-user.target.wants/usercrash.service.
Removed /etc/systemd/system/hprobe.timer.
Removed /etc/systemd/system/telemd-update-trigger.service.
Removed /etc/systemd/system/pstore-clean.service.
Removed /etc/systemd/system/pstore-probe.service.
Removed /etc/systemd/system/oops-probe.service.
Removed /etc/systemd/system/klogscanner.service.
Removed /etc/systemd/system/journal-probe.service.
Removed /etc/systemd/system/bert-probe.service.
removed '/etc/sysctl.d/80-coredump.conf'
removed '/etc/systemd/system.conf.d/40-watchdog.conf'
... Set server_delivery_enabled=true in /etc/telemetrics/telemetrics.conf
... Set record_retention_enabled=false in /etc/telemetrics/telemetrics.conf
*** Please reboot your system. ***

Follow the hints to reboot the system:

$ sudo reboot

To check the status of this tool:

$ sudo crashlogctl is-active

It will show the status of the related services like:

telemprobd : active
telempostd : active
acrnprobe  : inactive
usercrash  : inactive

Usage

The acrnprobe tool can work in two ways according to the existence of telemetrics-client on the system:

  1. If telemetrics-client doesn’t exist on the system, acrnprobe provides history_event (under /var/log/crashlog/history_event) to manage the crash and events records on the platform. But in this case, the records can’t be delivered to the backend.
  2. If telemetrics-client exists on the system, acrnprobe works as a probe of the telemetrics-client: it runs as a daemon autostarted when the system boots, and sends the crashlog path to the telemetrics-client that records events of interest and reports them to the backend using telemd the telemetrics daemon. The work flow of acrnprobe and telemetrics-client is shown in Figure 257:
digraph {
   bgcolor=transparent; rankdir=LR;
   node [shape="rectangle" style="filled" color="lightblue"]
   edge [fontsize="12" fontcolor="blue"]

   "acrnprobe" -> "telemetrics-client" [label="crashlog\npath"]
   "telemetrics-client" -> "backend"   [label="log\ncontent"]
}

Figure 257 acrnprobe and telemetrics-client workflow

Crashlog can be retrieved with telem_journal command:

$ telem_journal -i

Note

For more details of telemetrics, please refer the telemetrics-client and telemetrics-backend website.

ACRN-Crashlog also provides a tool debugger to dump the specific process information:

$ debugger <pid>

Note

You need to be root to use the debugger.

Source Code

The source code structure:

acrn-crashlog/
├── acrnprobe
│   └── include
├── common
│   └── include
├── data
└── usercrash
    └── include
  • acrnprobe: to gather all the crash and event logs on the platform, and probe on telemetrics-client. For the logs on hypervisor, it’s collected with acrnlog. For the log on SOS, the userspace crash log is collected with usercrash, and the kernel crash log is collected with the inherent mechanism like ipanic, pstore and etc. For the log on AaaG, it’s collected with monitoring the change of related folders on the sos image, like /data/logs/. acrnprobe also provides a flexible way to allow users to configure which crash or event they want to collect through the xml file easily.
  • common: some utils for logs, command and string.
  • data: configuration file, service files and shell script.
  • usercrash: to implement the tool which get the crash information for the crashing process in userspace.

acrnprobe

The acrnprobe detects all critical events on the platform and collects specific information for debug purpose. These information would be saved as logs, and the log path would be delivered to telemetrics-client as a record if the telemetrics-client existed on the system. For more detail on acrnprobe, please refer acrnprobe.

usercrash

The usercrash is a tool to get the crash info of the crashing process in userspace. It works in Client/Server model. Server is autostarted, and client is configured in core_pattern or coredump-wrapper, which will be triggered once crash occurs in userspace. For more detail on usercrash, please refer usercrash.