Re: [PATCH 02/32] sunrpc: fix encoder callback prototypes

[Jeff Layton <jlayton@redhat.com>]

On Tue, 2017-05-09 at 15:11 +0200, Christoph Hellwig wrote:
> On Tue, May 09, 2017 at 11:43:49AM +0200, Mkrtchyan, Tigran wrote:
> > just out of curiosity: you are talking about increasing type safety, but
> > at the same time replaces arguments to 'const void *data', which will accept
> > everything. Is there something special which I don't understand?
> 
> Nothing special - cast are potentially dangerous in general, and
> function pointer cases are especially dangerous as there is no
> verify the caller and callee signatures match at all.  As generic
> method call patterns need to have private data of some points they
> need to have a void pointer somewhere - either in the signature or
> as a pointer from a passed structure.  For those the compiler at least
> can do some basic sanity checking, and good static analysis tools can
> even verify we get the proper object using whole program analysis.

Strong ACK on all of this.

I've been bitten before (in userland code) by having a function that
took 3 arguments cast to something that took 2. So the callers ends up
passing in too few arguments, and the function then just ends up using
junk out of a register or off the the stack to satisfy the missing one.
Not fun to track down.

Christoph, for the first 13 patches, you can add:

Reviewed-by: Jeff Layton <jlayton@redhat.com>

I'll look over the remaining ones later.