Re: [DRAFT] mm/kprobes: Add generic kprobe_fault_handler() fallback definition

[Guenter Roeck]

On 7/2/19 10:35 PM, Anshuman Khandual wrote:
> On 07/01/2019 06:58 PM, Guenter Roeck wrote:
> > On 7/1/19 2:35 AM, Anshuman Khandual wrote:
> > > Architectures like parisc enable CONFIG_KROBES without having a definition
> > > for kprobe_fault_handler() which results in a build failure. Arch needs to
> > > provide kprobe_fault_handler() as it is platform specific and cannot have
> > > a generic working alternative. But in the event when platform lacks such a
> > > definition there needs to be a fallback.
> > >
> > > This adds a stub kprobe_fault_handler() definition which not only prevents
> > > a build failure but also makes sure that kprobe_page_fault() if called will
> > > always return negative in absence of a sane platform specific alternative.
> > >
> > > While here wrap kprobe_page_fault() in CONFIG_KPROBES. This enables stud
> > > definitions for generic kporbe_fault_handler() and kprobes_built_in() can
> > > just be dropped. Only on x86 it needs to be added back locally as it gets
> > > used in a !CONFIG_KPROBES function do_general_protection().
> > >
> > > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> > > ---
> > > I am planning to go with approach unless we just want to implement a stub
> > > definition for parisc to get around the build problem for now.
> > >
> > > Hello Guenter,
> > >
> > > Could you please test this in your parisc setup. Thank you.
> >
> > With this patch applied on top of next-20190628, parisc:allmodconfig builds
> > correctly. I scheduled a full build for tonight for all architectures.
>
> How did that come along ? Did this pass all build tests ?

Let's say it didn't find any failures related to this patch. I built on top of
next-20190701 which was quite badly broken for other reasons. Unfortunately,
next-20190702 is much worse, so retesting would not add any value at this time.
I'd say go for it.

Guenter