Re: [PATCH v3 net-next 01/23] lib: add reference counting tracking infrastructure

[Eric Dumazet <edumazet@google.com>]

On Wed, Dec 15, 2021 at 2:57 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
>
> On 12/15/21 11:41, Eric Dumazet wrote:
> > On Wed, Dec 15, 2021 at 2:38 AM Eric Dumazet <edumazet@google.com> wrote:
> >>
> >> On Wed, Dec 15, 2021 at 2:18 AM Jiri Slaby <jirislaby@gmail.com> wrote:
> >> >
> >> > On 05. 12. 21, 5:21, Eric Dumazet wrote:
> >> > > From: Eric Dumazet <edumazet@google.com>
> >> > >
> >> > > It can be hard to track where references are taken and released.
> >> > >
> >> > > In networking, we have annoying issues at device or netns dismantles,
> >> > > and we had various proposals to ease root causing them.
> >> > ...
> >> > > --- a/lib/Kconfig
> >> > > +++ b/lib/Kconfig
> >> > > @@ -680,6 +680,11 @@ config STACK_HASH_ORDER
> >> > >        Select the hash size as a power of 2 for the stackdepot hash table.
> >> > >        Choose a lower value to reduce the memory impact.
> >> > >
> >> > > +config REF_TRACKER
> >> > > +     bool
> >> > > +     depends on STACKTRACE_SUPPORT
> >> > > +     select STACKDEPOT
> >> >
> >> > Hi,
> >> >
> >> > I have to:
> >> > +       select STACKDEPOT_ALWAYS_INIT
> >> > here. Otherwise I see this during boot:
> >> >
> >>
> >> Thanks, I am adding Vlastimil Babka to the CC
> >>
> >> This stuff has been added in
> >> commit e88cc9f5e2e7a5d28a1adf12615840fab4cbebfd
> >> Author: Vlastimil Babka <vbabka@suse.cz>
> >> Date:   Tue Dec 14 21:50:42 2021 +0000
> >>
> >>     lib/stackdepot: allow optional init and stack_table allocation by kvmalloc()
> >>
> >>
> >
> > (This is a problem because this patch is not yet in net-next, so I really do
> > not know how this issue should be handled)
>
> Looks like multiple new users of stackdepot start appearing as soon as I
> touch it :)
>
> The way we solved this with a new DRM user was Andrew adding a fixup to my
> patch referenced above, in his "after-next" section of mm tree.
> Should work here as well.
>
> ----8<----
> From 0fa1f25925c05f8c5c4f776913d84904fb4c03a1 Mon Sep 17 00:00:00 2001
> From: Vlastimil Babka <vbabka@suse.cz>
> Date: Wed, 15 Dec 2021 11:52:10 +0100
> Subject: [PATCH] lib/stackdepot: allow optional init and stack_table
>  allocation by kvmalloc() - fixup4
>
> Due to 4e66934eaadc ("lib: add reference counting tracking infrastructure")
> landing recently to net-next adding a new stack depot user in lib/ref_tracker.c
> we need to add an appropriate call to stack_depot_init() there as well.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---

I guess this minimal fix will do.

In the future, when net-next (or net tree) has everything in place,
I will probably un-inline ref_tracker_dir_init() to avoid pulling
all these includes...

Reviewed-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jiri Slab <jirislaby@gmail.com>