Re: [PATCH] x86/mm/ptdump: Fix soft lockup in page table walker.

From: Thomas Gleixner
Date: Fri Feb 10 2017 - 06:34:40 EST

On Fri, 10 Feb 2017, Dmitry Vyukov wrote:
> This is the right thing to do per se, but I am concerned that now
> people will just suffers from slow boot (it can take literally
> minutes) and will not realize the root cause nor that it's fixable
> (e.g. with rodata=n) and will probably just blame KASAN for slowness.
> Could we default this rodata check to n under KASAN? Or at least print
> some explanatory warning message before doing marking rodata (it
> should be printed right before "hang", so if you stare at it for a
> minute during each boot you realize that it may be related)? Or
> something along these lines. FWIW in my builds I just always disable
> the check.

That certainly makes sense and we emit such warnings in other places
already (lockdep, trace_printk ...)