Re: [PATCH] kallsyms: don't leak address when printing symbol

[Sergey Senozhatsky]

On (11/08/17 22:35), Steven Rostedt wrote:
> On Thu,  9 Nov 2017 12:50:29 +1100
> "Tobin C. Harding" <me@xxxxxxxx> wrote:
> 
> > Currently if a pointer is printed using %p[ssB] and the symbol is not
> > found (kallsyms_lookup() fails) then we print the actual address. This
> > leaks kernel addresses. We should instead print something _safe_.
> > 
> > Print "<no-symbol>" instead of kernel address.
> 
> Ug, ftrace requires this to work as is, as it uses it to print some
> addresses that may or may not be a symbol.
> 
> If anything, can this return a success or failure if it were to find a
> symbol or not, and then something like ftrace could decide to use %x if
> it does not.
> 
> And yes, ftrace leaks kernel addresses all over the place, that's just
> the nature of tracing the kernel.
> 

agree, I kinda suspect that that "0x%lx" sometimes can be useful.
at least one can tell if the frame is from modules or kernel, and
objdump it may be.

	-ss