Hashed pointer issues

From: Anna-Maria Gleixner
Date: Mon Apr 30 2018 - 11:51:02 EST


I stumbled over an issue with hashed pointers and tracing.

I'm using trace points for examination and on error the trace buffers
are dumped. The error occurs when entropy has not been set up, so the
pointers are not hashed and only (ptrval) is printed instead. The
pointers are required to distinguish the different objects in the

Beside workarounds like patching lib/vsprintf.c helpers before testing
or dumping trace buffers later (given that kernel comes up properly
and entropy is set up), is there a possible generic solution for this
issue? A commandline option for disabling the pointer obfuscation
would be a pretty handy tool.