Christopher M. Riedl wrote:
On Fri Apr 24, 2020 at 9:15 AM, Steven Rostedt wrote:
On Thu, 23 Apr 2020 18:21:14 +0200
Christophe Leroy <christophe.le...@c-s.fr> wrote:
> Le 23/04/2020 à 17:09, Naveen N. Rao a écrit :
> > With STRICT_KERNEL_RWX, we are currently ignoring return value from
> > __patch_instruction() in do_patch_instruction(), resulting in the error
> > not being propagated back. Fix the same.
>
> Good patch.
>
> Be aware that there is ongoing work which tend to wanting to replace
> error reporting by BUG_ON() . See
> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=166003
Thanks for the reference. I still believe that WARN_ON() should be used
in
99% of the cases, including here. And only do a BUG_ON() when you know
there's no recovering from it.
In fact, there's still BUG_ON()s in my code that I need to convert to
WARN_ON() (it was written when BUG_ON() was still acceptable ;-)
Figured I'd chime in since I am working on that other series :) The
BUG_ON()s are _only_ in the init code to set things up to allow a
temporary mapping for patching a STRICT_RWX kernel later. There's no
ongoing work to "replace error reporting by BUG_ON()". If that initial
setup fails we cannot patch under STRICT_KERNEL_RWX at all which imo
warrants a BUG_ON(). I am still working on v2 of my RFC which does
return any __patch_instruction() error back to the caller of
patch_instruction() similar to this patch.
Ok, that's good to know. I will drop this patch from my series, since
this can be done independently of the other changes.
- Naveen
