From: Kees Cook <kees@kernel.org>
To: "Christoph Lameter (Ampere)" <cl@gentwo.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
linux-mm@kvack.org, Miguel Ojeda <ojeda@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Marco Elver <elver@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH 5/5] [DEBUG] slab: Report number of NULLings
Date: Tue, 25 Mar 2025 12:45:10 -0700 [thread overview]
Message-ID: <202503251244.CA3E0F8@keescook> (raw)
In-Reply-To: <e3437446-798d-f4f3-11d7-675f8886575b@gentwo.org>
On Mon, Mar 24, 2025 at 09:16:47AM -0700, Christoph Lameter (Ampere) wrote:
> On Fri, 21 Mar 2025, Kees Cook wrote:
>
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 2717ad238fa2..a4740c8b6ccb 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -469,6 +469,8 @@ void __kfree(const void *objp);
> > void __kfree_sensitive(const void *objp);
> > size_t __ksize(const void *objp);
> >
> > +extern atomic_t count_nulled;
>
> That is a scalability issue. Use a vmstat counter instead?
Yeah, this patch (marked "DEBUG") isn't intended for upstreaming. It was
just a quick hack to get a ballpark statistic. :)
--
Kees Cook
next prev parent reply other threads:[~2025-03-25 19:45 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-21 20:40 [RFC 0/5] slab: Set freed variables to NULL by default Kees Cook
2025-03-21 20:40 ` [PATCH 1/5] treewide: Replace kfree() casts with union members Kees Cook
2025-03-23 10:26 ` David Laight
2025-03-21 20:40 ` [PATCH 2/5] treewide: Prepare for kfree() to __kfree() rename Kees Cook
2025-03-21 20:40 ` [PATCH 3/5] compiler_types: Introduce __is_lvalue() Kees Cook
2025-03-22 3:38 ` Jann Horn
2025-03-22 7:03 ` Kees Cook
2025-03-21 20:41 ` [PATCH 4/5] slab: Set freed variables to NULL by default Kees Cook
2025-03-22 1:50 ` Jann Horn
2025-03-22 7:18 ` Kees Cook
2025-03-27 19:23 ` Jann Horn
2025-03-27 19:42 ` Matthew Wilcox
2025-03-21 20:41 ` [PATCH 5/5] [DEBUG] slab: Report number of NULLings Kees Cook
2025-03-24 16:16 ` Christoph Lameter (Ampere)
2025-03-25 19:45 ` Kees Cook [this message]
2025-03-27 13:00 ` [RFC 0/5] slab: Set freed variables to NULL by default Harry Yoo
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