Will high revs of the engine be a problem?

One of my friends drove my cx-9 yesterday, and he incidentally used "M" instead of "D" mode. So, the tachometer went all the way to 7000-8000 readline, for about one minute...

so far, i didn't notice any difference. Just curious if that hurts the engine? or anything I need to worry about at all?

dont ever let your friend drive your CX9 again...........
No, you should be just fine

If your engine computer has not been altered by a software modification, then you have a rev limiter to protect the engine from damage. Also, the max horsepower is achieved at upper rpm's anyhow. No worries.

Don't worry. A couple seconds into the red zone will not hurt the engine.
Actually, CX9 has analog gauges. The actual highest rpm might not be that high.
Fuel gets cut off when the engine hits red line.

One mechanic told me once that it is good to, once in a while, rev your engine near red line (assumed it is warmed up).
It keeps the engine healthy by clearing up unwanted residuals in the exhaust system.
He said that whenever customers have idle stability issue, revving the engine for a few seconds is the first thing he would try....

thanks a lot for all you inputs!