Printk specifiers for __user pointers

[Alan Stern]

To the VSPRINTF maintainers:

Documentation/core-api/printk-formats.rst lists a large number of format 
specifiers for pointers of various sorts.  Yet as far as I can see, 
there is no specifier meant for use with __user pointers.

The security implications of printing the true, unmangled value of a 
__user pointer are minimal, since doing so does not leak any kernel 
information.  So %px would work, but tools like checkpatch.pl don't like 
it.

Should a new specifier be added?  If not, should we simply use %px?

Alan Stern