ardupilot/libraries/AP_CANManager
Andrew Tridgell 322b7520de AP_CANManager: fixed critical race in log_text()
the AP_CANManager::log_text() gets called from debug logging in
AP_DroneCAN. It is a method on a common AP_CANManager object which is
shared by multiple AP_DroneCAN threads.

if two threads call the debug log messages at the same time then we
can end up with _log_pos greater than LOG_BUFFER_SIZE (1024) and
overwrite past the end of the buffer

in the crash_dump we have for this case the next piece of memory was
hal.can[0], and the overwrite of the buffer had corrupted the
MessageRam_ structurre in the ChibiOS CAN interface code. That led to
a hardfault on receive of a CAN message

Note that this issue only happens if CAN_LOGLEVEL is set to greater
than zero, and the default is zero. So users can avoid the bug by
checking they have not changed CAN_LOGLEVEL.

Also, this is likely an issue that only happens on startup, as once
the two AP_DroneCAN threads are fully running they have the same
thread priority so can't pre-empt each other. During startup some
messages are sent from the main thread which has a different priority
to the AP_DroneCAN threads, and can thus trigger this issue
2024-12-14 15:41:38 +11:00
..
AP_CAN.h AP_CANManager: Add multiCAN interface 2024-02-27 10:59:41 +11:00
AP_CANDriver.h AP_CANManager: use 32 bit timeout for write_aux_frame 2024-11-17 10:38:12 +11:00
AP_CANIfaceParams.cpp AP_CANManager: support CAN frame logging 2024-12-11 08:43:56 +11:00
AP_CANManager.cpp AP_CANManager: fixed critical race in log_text() 2024-12-14 15:41:38 +11:00
AP_CANManager.h AP_CANManager: support CAN frame logging 2024-12-11 08:43:56 +11:00
AP_CANManager_CANDriver_Params.cpp AP_CANManager: correct includes 2024-03-20 18:45:52 +11:00
AP_CANManager_config.h AP_CANManager: support CAN frame logging 2024-12-11 08:43:56 +11:00
AP_CANSensor.cpp AP_CANManager: use 32 bit timeout for write_frame 2024-11-17 10:38:12 +11:00
AP_CANSensor.h AP_CANManager: use 32 bit timeout for write_frame 2024-11-17 10:38:12 +11:00
AP_SLCANIface.cpp AP_CANManager: Integrate methods for converting hexadecimal characters to numbers 2024-09-25 08:48:44 +10:00
AP_SLCANIface.h AP_CANManager: reimplement with BinarySemaphore 2024-01-03 07:37:05 +11:00
LogStructure.h AP_CANManager: support CAN frame logging 2024-12-11 08:43:56 +11:00
README.md AP_CANManager: update docs 2023-09-01 13:04:59 +10:00

README.md

Testing And Debugging

Testing under SITL

A wide range of DroneCAN peripherals are supported in the SITL simulation system. The simplest way of starting a DroneCAN enabled simulated vehicle is to use sim_vehicle.py.

For a quadplane use: sim_vehicle.py with the option -f quadplane-can

For a quadcopter use: sim_vehicle.py with the option -f quad-can