AP_Camera_Backend::Write_CameraInfo does not handle uninitialized location

[blaab2]

Bug report

Issue details

This is a HAL_BOARD_SITL bug report. The panic function within libraries/AP_Common/Location.cpp is triggered if a camera trigger is requested without the location being available.

code details

This occurs as the

ardupilot/libraries/AP_Common/Location.cpp

Line 109 in 7601c83

AP_HAL::panic("Should not be called on invalid location: Location cannot be (0, 0, 0)");

panic function will be raised by AP_Camera_Backend::Write_CameraInfo if camera trigger is requested (for example via mission planner) and location is not known yet. The unguarded call to current_loc.get_alt_cm raises this.

fix

ardupilot/libraries/AP_Camera/AP_Camera_Logging.cpp

Line 33 in 7601c83

if (!current_loc.get_alt_cm(Location::AltFrame::ABSOLUTE, altitude_cm)) {

and

ardupilot/libraries/AP_Camera/AP_Camera_Logging.cpp

Line 37 in 7601c83

if (!current_loc.get_alt_cm(Location::AltFrame::ABOVE_HOME, altitude_rel_cm)) {

should be
if (current_loc.initialised() && !current_loc.get_alt_cm(Location::AltFrame::ABSOLUTE, altitude_cm)) {
and
if (current_loc.initialised() && !current_loc.get_alt_cm(Location::AltFrame::ABOVE_HOME, altitude_rel_cm)) {

I could send a PR if requested.

Version
master branch
4.7.0-dev

Platform
[?] All
[ ] AntennaTracker
[X] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

Airframe type
irrelevant

Hardware type
HAL_BOARD_SITL

Logs

#5  0x000055ebb20e1175 in AP_HAL::panic (errormsg=0x55ebb2231600 "Should not be called on invalid location: Location cannot be (0, 0, 0)") at ../../libraries/AP_HAL_SITL/system.cpp:51
        ap = {{gp_offset = 8, fp_offset = 48, overflow_arg_area = 0x7ffcabb23be0, reg_save_area = 0x7ffcabb23b20}}

[rmackay9]

Hi @blaab2,

Thanks very much for the report. I've created a PR to resolve the issue and I've "Co-Authored" it with you to give you the credit because you've done most of the work. Please tell me if it looks OK to you.

Thanks very much!

[rmackay9]

This has been merged to master now so I'll close this.

I don't think we will back port this to 4.6 if that's OK because it's not high risk. It only occurs in SITL.