Re: [GIT PULL tools] Linux kernel memory model

From: Paul E. McKenney
Date: Fri Feb 09 2018 - 06:30:08 EST


On Fri, Feb 09, 2018 at 10:11:10AM +0100, Andrea Parri wrote:
> On Thu, Feb 08, 2018 at 09:02:19PM +0100, Peter Zijlstra wrote:
> > On Thu, Feb 08, 2018 at 06:41:06PM +0000, Patrick Bellasi wrote:
> > > Hi Paul,
> > > thanks to you and all the involved guys for this useful tool.
> > >
> > > I give it a try today and found that by installing herd7 by just
> > > following the instruction in herdtools7/INSTALL.md, and precisely
> > > installing it via:
> > >
> > > opam install herdtools7
> > >
> > > it seems to give you a tool which fails to run the basic example in
> > > your README with this error:
> > >
> > > File "./linux-kernel.def", line 44, characters 29-30: unexpected '-' (in macros)
> > >
> > > As suggested by Will, by building instead herd7 HEAD (commit 44d69c2)
> > > everything works fine.
> > >
> > > Maybe it's a know issue, in case just ignore me. :)
> > >
> > > Otherwise, maybe it can be worth to add to the README a note on which
> > > minimum version of the herd7 tool is required.
> > >
> > > opma version (not working) : 7.47, Rev: exported
> > > master version (working for me) : 7.47+7(dev), Rev: 44d69c2b1b5ca0f97bd138899d31532ee5e4e084
> >
> > Urgh. So that's why it wouldn't work.
> >
> > I remember Paul saying you needed the latest version, which is why I
> > rebuild from opam, but building top of git is a bit much.
>
> +1
>
> _Sadly_ enough, co-developers and I were aware of this issue,
> but it was only mildly reported here (c.f.,
>
> https://marc.info/?l=linux-kernel&m=151638196427685&w=2 ).
>
> This bisects to that (crazy):
>
> 2d5fba7782d669c6a1cc577dbc3bf507780273bb
> ("linux-kernel*: Make RCU identifiers match ASPLOS paper")
>
> From repo.: https://github.com/aparri/memory-model
>
> which not only did break 7.47, but also made the bell uglier
> by mixing dashes and underscores in a very same block.
>
> As a solution to this issue, I can envisage a partial revert
> of that commit (just replace those dashes); Paul, Jade, Luc:
> any better solution?
>
> (Sorry for being late on IRC, glad this came out here,)

Or maybe a 7.48 release?

Thanx, Paul