Re: [PATCH] sh: Stop printing the virtual memory layout

Kaiwan N Billimoria
2020-03-08T12:25:48Z

On Thu, Mar 5, 2020 at 8:48 PM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
>
> On 3/5/20 4:10 PM, Arvind Sankar wrote:
> > For security, don't display the kernel's virtual memory layout.
> >
> > Kees Cook points out:
> > "These have been entirely removed on other architectures, so let's
> > just do the same for ia32 and remove it unconditionally."
> >
> > 071929dbdd86 ("arm64: Stop printing the virtual memory layout")
> > 1c31d4e96b8c ("ARM: 8820/1: mm: Stop printing the virtual memory layout")
> > 31833332f798 ("m68k/mm: Stop printing the virtual memory layout")
> > fd8d0ca25631 ("parisc: Hide virtual kernel memory layout")
> > adb1fe9ae2ee ("mm/page_alloc: Remove kernel address exposure in free_reserved_area()")
> Aww, why wasn't this made configurable? I found these memory map printouts
> very useful for development.

Same here! IMO, the kernel segment layout is useful for devs/debug purposes.
Perhaps:
a) all these printk's could be gathered into one function and invoked
only when DEBUG (or equivalent) is defined?
b) else, the s/pr_info/pr_devel approach with %pK should be good?
-Kaiwan.