Re: [PATCH 3/3] utrace-based ftrace "process" engine, v2

[Roland McGrath <roland@redhat.com>]

> I do have a really large objection of merging the current messy double
> ptrace implementation.  If current utrace based ptrace isn't 100% ready
> there's absolutely no point in merging it.  

There is no "current" utrace-ptrace implementation.  I haven't proposed
one for merging.  When one is ready and working, we can discuss its actual
technical details then.

> Other user would be even better, e.g. the seccomp rewrite.

The seccomp rewrite is a very simple user for which I have a prototype
patch.  (It needs testing, but that should be easy enough.)  The only
real complexity there is in deciding how to merge those changes.
Its components are:

* clean up Kconfig
* remove old arch/asm hooks
** mips
** powerpc
** sh
** sparc
** x86
* replace kernel/seccomp.c with utrace-based one

Except for the first one, doing it in small incremental changes would
leave some intermediate states with no seccomp feature usable in the
tree.  (And, of course, CONFIG_SECCOMP will require CONFIG_UTRACE
thereafter.)  Please advise on how many pieces to slice it into and
how to stage the merging.


Thanks,
Roland