Hi RT-experts,

Duration tests with RT enabled v4.14 kernels on our ARM iMX6Q systems
are showing "Unable to handle kernel NULL pointer dereference at
virtual address" after running for some months. The same tests on NON-
RT kernels don't show any problem and have been running without any
problems for more than 20 months now.

I've been updating the tests from time to time with more recent
kernels. Testing is basically done with cyclictest, in parallel with
some load scripts/hackbench. Please have a look at the kernel traces:
4.14.71-rt44  -> https://paste.debian.net/1152206/
4.14.106-rt56 -> https://paste.debian.net/1152204/
4.14.146-rt67 -> https://paste.debian.net/1152202/

I've seen the v4.14-rt branch got some fixes, so my questions are:
1) is problem I'm facing known and fixed in v4.14-rt, or
2) is the problem I'm seeing a new issue probably still unfixed in
4.14.183-rt83 (which I'm testing right now)?

Any help is highly appreciated!

Thanks,
Henri