Ardupilot: MavFTP: MAVFTP got stucked and fcu reboot.

[liang-tang]

Bug report

this make MAVFTP got stucked and fcu reboot.

step by step:
1.clean up waypoints.
2.reboot.
3.use CTRL+X to Show FTP window.
4.delete whole TERRAIN directory.
5.reboot.
6.write waypoints. (remake TERRAIN directory)
7.use CTRL+X to Show FTP window.

1. nothing we can get from APM directory and also FCU reboot probablly.
   

But if exchange step 6 and 7, no issue occur.

Version
master branch today
Platform
[ ] All
[ ] AntennaTracker
[ ] Copter
[ * ] Plane
[ ] Rover
[ ] Submarine

Airframe type
defalut after reset
Hardware type
mindpx-v2
Logs
no log

[WickedShell]

I can't reproduce this with a cube.

[liang-tang]

I can't reproduce this with a cube.

I'll try it again.

[liang-tang]

there is a video that reproduce with cube.
MP: 1.3.69
ArduPlane: V4.1.0dev (19c02471)
https://drive.google.com/open?id=10vKB2JaKgDaKCpUyhL3DW2G_Hw0QPcJB

[WickedShell]

@rmackay9's steps to repro (from #13536):

1. flash master onto the Cube Black (I was using "ArduCopter V4.0.3-dev 0cf747c")
2. restore all parameters to their defaults
3. open Mission Planner and press Ctrl-X to connect using MAVFTP
4. attempt to open the APM directory

[rmackay9]

I've reproduced this in master, Copter-4.0.1 and Copter-4.0.2-rc4

[WickedShell]

Repros on plane as well.

[rmackay9]

This is fixed in master and is included in Copter-4.0.2

@liang-tang, thanks very much for the report!

[liang-tang]

SITL with plane 4.0.5beta1
Stack overflow in thread FTP

[peterbarker]

Stack trace would be good. You will need to enable the operation according to the instructions there.

Steps to reproduce would be great!

[rmackay9]

@liang-tang,

Thanks very much for the follow-up.

By the way, I tried to reproduce this on Copter (latest) but wasn't able to. If it can be reproduced with Copter-4.0.3-rc1 then I'll stick it back on the Copter-4.0 issues list.

I think with Copter-4.0 we've done a good job of tracking and resolving bugs so getting it on this list is another good way to ensure it's not forgotten.

[liang-tang]

@rmackay9
The code is at /home/ubuntu/My_ArduPilot, and switched to Copter-4.0.3-rc1 branch.
Setp 1,
in directory /home/ubuntu/My_ArduPilot, execute

./Tools/autotest/sim_vehicle.py -v ArduCopter

Setp 2,
use CTRL+X to get content, then stack overflow.

BTW,
after increased stack size of ftp thread to 8k(just have a try), ftp works well.
and I got the root directory of ubuntu(version 16.04)

It may be that too many files are read, causing a stack overflow. Stack usage is positively correlated with the number of files read.

[peterbarker]

Thanks @liang-tang ! Reproduced on ArduCopter-beta, but does not trivially reproduce on master.

@rmackay9 we might be missing a patch into the Copter beta?

[liang-tang]

@peterbarker we read ardupilot directory on master, but read root directory on Copter beta, different directory.

[peterbarker]

f504009287221c7fda9cfa9c389a13af702aa9fd is probably the missing patch

We don't run the check-stack stuff on master because the pthread-attr-set-stack call we make doesn't work correctly.

Plane beta is also missing the patch.

[rmackay9]

I think we can close this issue because it's fixed in master. Just as a side note, getting the fix into a stable branch is a separate thing not related to having the issue open.

[Davidsastresas]

I just found this thread because I got this issue reported by SITL in ubuntu 20.04. In 4.0.5 apparently the f504009 patch was not present and the error was there, I cherry-picked the patch and now it is working nicely.

[rmackay9]

@Davidsastresas, txs for the feedback. I think this patch is included in Plane-4.0.6 that is available for beta testing. Plane isn't my baby but it should be there.

[peterbarker]

That patch is not in the current ArduPlane beta.

[Davidsastresas]

It would be cool to include it, the patch has been there since January!

[rmackay9]

@Davidsastresas, Tridge has confirmed that this is included in the Plane beta so if you get a chance to test with the latest beta that would be good, txs again!

[peterbarker]

@Davidsastresas so the patch isn't there but the code is. Are you able to reproduce this bug on either of Copter or Plane betas?

[Davidsastresas]

I just checked both, copter and plane betas and it works so the patch should be there. Thank you!