Thread safety in custom rendering sensor system (DopplerVelocityLogSystem.cc)

[5p00kk]

Environment

Description

In DopplerVelocityLogSystem.cc there are time-related variables: nextUpdateTime, simTime. They appear to be used by both: the rendering thread (OnRedner, PostRender) and physics thread (DoPostUpdate). There seems to be no thread safety for these variables, compared to for instance pendingRequests which is atomic.

[azeey]

Thanks for catching those. There does seem to be a race condition on those variables. Would you be able to submit a PR?

[sauk2]

@azeey Could I work on this?

[azeey]

Yes, please go ahead. I'll assign it to you.

[sauk2]

Yes, please go ahead. I'll assign it to you.

Would like to know your opinion on a possible implementation idea here:

• Have a single mutex to protect both simTime and nextUpdateTime.
• Always lock the mutex using lock_guard at the start of the OnRender and OnPostRender callbacks.
• This if block in DoPostUpdate uses both variables. Break it down into a nested if and lock the mutex inside it.