Re: [PATCH 2/5] padata: make padata_free_shell() to respect pd's ->refcnt

[Daniel Jordan]

On Wed, Nov 09, 2022 at 02:02:37PM +0100, Nicolai Stange wrote:
> Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> writes:
> 
> > On Wed, Oct 19, 2022 at 10:37:05AM +0200, Nicolai Stange wrote:
> >> 
> >> Fixes: 07928d9bfc81 ("padata: Remove broken queue flushing")
> >
> > It looks like this issue goes back to the first padata commit.  For
> > instance, pd->refcnt goes to zero after the last _priv is serialized,
> > padata_free is called in another task, and a particularly sluggish
> > padata_reorder call touches pd after.
> >
> > So wouldn't it be
> >
> > Fixes: 16295bec6398 ("padata: Generic parallelization/serialization interface")
> 
> I chose 07928d9bfc81 ("padata: Remove broken queue flushing"), because
> that one reads like it fixed a couple of much more severe padata
> lifetime issues, it only missed the relatively minor one addressed here,
> in a sense.
> 
> Or to put it the other way around: if one were to backport this patch
> here, 07928d9bfc81 should probably get picked first, I think.
> 
> But I'd be fine with any Fixes tag, of course, I don't have a strong
> opinion on this matter.

Ok, makes sense, your Fixes is fine then.  Please put that justification
in the changelog for the next version.