Re: [PATCH v2 3/5] signal: Add unsafe_copy_siginfo_to_user()

[Christophe Leroy]

Le 02/09/2021 à 08:54, Christoph Hellwig a écrit :
> On Mon, Aug 23, 2021 at 03:35:53PM +0000, Christophe Leroy wrote:
> > In the same spirit as commit fb05121fd6a2 ("signal: Add
> > unsafe_get_compat_sigset()"), implement an 'unsafe' version of
> > copy_siginfo_to_user() in order to use it within user access blocks.
> >
> > For that, also add an 'unsafe' version of clear_user().
>
> I'm a little worried about all these unsafe helper in powerpc and the
> ever increasing scope of the unsafe sections.  Can you at least at
> powerpc support to objtool to verify them?  objtool verifications has
> helped to find quite a few bugs in unsafe sections on x86.

Ok, I've started looking at it, I have not found any work at all on 
objtool for powerpc. I'll see if I can draft something from the ARM64 
tentatives.

Christophe