Freeing (vfree-ing) pointer to volatile data

Question

volatile seems to be a never ending question of every one. I thought I knew everything about it, but then I encountered this:

So, I have a piece of memory s

Answer 1

My conclusion was that just casting the pointer to void * would not cause a problem and the fact that free and vfree don't directly accept pointers to volatile data is just something that was overlooked.

Answer 2

The vfree function (and every sane deallocation function in general) does not care about your actual data (be it volatile or not). It just expects a (valid) pointer (think: passing the pointer as a long value in a CPU register).

Based on that value, the function will:

1. call the SLAB/SLUB to free the memory
2. remove the memory mapping

So yes, casting to a void * will not cause any harm at runtime.