This bug has been copied from bug #450094 and has been proposed to be backported to 4.5 z-stream (EUS).
This bugzilla has Keywords: Regression. Since no regressions are allowed between releases, it is also being proposed as a blocker for this release. Please resolve ASAP.
Committed in 55.0.19.EL
Created attachment 310149 [details] soft lockup tracer
RHEL-4.5 EUS doesn't have original patch for mmap(), so it hasn't any regression. Patch was wrongly proposed to 4.5.z and included in it, I remove it from sources and close the bug.