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

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

[Vlastimil Babka]

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>
---
 include/linux/ref_tracker.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index c11c9db5825c..60f3453be23e 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -4,6 +4,7 @@
 #include <linux/refcount.h>
 #include <linux/types.h>
 #include <linux/spinlock.h>
+#include <linux/stackdepot.h>
 
 struct ref_tracker;
 
@@ -26,6 +27,7 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	spin_lock_init(&dir->lock);
 	dir->quarantine_avail = quarantine_count;
 	refcount_set(&dir->untracked, 1);
+	stack_depot_init();
 }
 
 void ref_tracker_dir_exit(struct ref_tracker_dir *dir);
-- 
2.34.1

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

[Eric Dumazet]

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>

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

[Jiri Slaby]

On 15. 12. 21, 12:08, Eric Dumazet wrote:
> Reported-by: Jiri Slab <jirislaby@gmail.com>

(I am not the allocator :P.)

-- 
js

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

[Eric Dumazet]

On Wed, Dec 15, 2021 at 3:09 AM Jiri Slaby <jirislaby@gmail.com> wrote:
>
> On 15. 12. 21, 12:08, Eric Dumazet wrote:
> > Reported-by: Jiri Slab <jirislaby@gmail.com>
>
> (I am not the allocator :P.)

Ah, it took me a while to understand, sorry for the typo ;)