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Date: Wed, 27 Dec 2023 14:10:05 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Andrey Konovalov <andreyknvl@gmail.com>
Cc: kernel test robot <lkp@intel.com>, andrey.konovalov@linux.dev, Marco
 Elver <elver@google.com>, oe-kbuild-all@lists.linux.dev, Linux Memory
 Management List <linux-mm@kvack.org>, Alexander Potapenko
 <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin
 <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH mm] kasan: stop leaking stack trace handles
Message-Id: <20231227141005.14e278c3f08dd0d64004dbf7@linux-foundation.org>
In-Reply-To: <CA+fCnZfZMhkqOvsvavJ-YTddY4kniP+sWFZRYy+nd3+8_C9hPA@mail.gmail.com>
References: <20231226225121.235865-1-andrey.konovalov@linux.dev>
	<202312280213.6j147JJb-lkp@intel.com>
	<20231227132311.557c302e92bdc9ffb88b42d5@linux-foundation.org>
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On Wed, 27 Dec 2023 22:42:40 +0100 Andrey Konovalov <andreyknvl@gmail.com> wrote:

> On Wed, Dec 27, 2023 at 10:23 PM Andrew Morton
> <akpm@linux-foundation.org> wrote:
> >
> > Thanks, I added this fix:
> >
> > --- a/mm/kasan/generic.c~kasan-stop-leaking-stack-trace-handles-fix
> > +++ a/mm/kasan/generic.c
> > @@ -503,7 +503,7 @@ void kasan_init_object_meta(struct kmem_
> >          */
> >  }
> >
> > -void release_alloc_meta(struct kasan_alloc_meta *meta)
> > +static void release_alloc_meta(struct kasan_alloc_meta *meta)
> >  {
> >         /* Evict the stack traces from stack depot. */
> >         stack_depot_put(meta->alloc_track.stack);
> > @@ -514,7 +514,7 @@ void release_alloc_meta(struct kasan_all
> >         __memset(meta, 0, sizeof(*meta));
> >  }
> >
> > -void release_free_meta(const void *object, struct kasan_free_meta *meta)
> > +static void release_free_meta(const void *object, struct kasan_free_meta *meta)
> >  {
> >         /* Check if free meta is valid. */
> >         if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREE_META)
> > _
> >
> 
> Could you mark them as "static inline" even?

That's rather old-fashioned.  Nowadays gcc is supposed to work out
whether or not to inline things, and we override that with noinline and
__always_inline.