From: Andrey Konovalov <andreyknvl@gmail.com>
To: Marco Elver <elver@google.com>
Cc: andrey.konovalov@linux.dev, Mark Rutland <mark.rutland@arm.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
kasan-dev@googlegroups.com,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Catalin Marinas <catalin.marinas@arm.com>,
Peter Collingbourne <pcc@google.com>,
Feng Tang <feng.tang@intel.com>,
stable@vger.kernel.org, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH] kasan, slub: fix HW_TAGS zeroing with slub_debug
Date: Wed, 5 Jul 2023 15:19:06 +0200 [thread overview]
Message-ID: <CA+fCnZenzRuxS4qjzFiYm05zNxHBSAkTUK7-1zixXXDUQb3g3w@mail.gmail.com> (raw)
In-Reply-To: <CANpmjNO+spktteYZezk7PGLFOyoeuFyziKiU-1GXbpeyKLZLPg@mail.gmail.com>
On Wed, Jul 5, 2023 at 2:51 PM Marco Elver <elver@google.com> wrote:
>
> On Wed, 5 Jul 2023 at 14:44, <andrey.konovalov@linux.dev> wrote:
> >
> > From: Andrey Konovalov <andreyknvl@google.com>
> >
> > Commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated
> > kmalloc space than requested") added precise kmalloc redzone poisoning
> > to the slub_debug functionality.
> >
> > However, this commit didn't account for HW_TAGS KASAN fully initializing
> > the object via its built-in memory initialization feature. Even though
> > HW_TAGS KASAN memory initialization contains special memory initialization
> > handling for when slub_debug is enabled, it does not account for in-object
> > slub_debug redzones. As a result, HW_TAGS KASAN can overwrite these
> > redzones and cause false-positive slub_debug reports.
> >
> > To fix the issue, avoid HW_TAGS KASAN memory initialization when slub_debug
> > is enabled altogether. Implement this by moving the __slub_debug_enabled
> > check to slab_post_alloc_hook. Common slab code seems like a more
> > appropriate place for a slub_debug check anyway.
> >
> > Fixes: 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested")
> > Cc: <stable@vger.kernel.org>
> > Reported-by: Mark Rutland <mark.rutland@arm.com>
>
> Is it fixing this issue:
>
> https://lore.kernel.org/all/20230628154714.GB22090@willie-the-truck/
Yes, my bad, messed up the Reported-by tag. The correct one should be:
Reported-by: Will Deacon <will@kernel.org>
> Other than the question above, it looks sane:
>
> Acked-by: Marco Elver <elver@google.com>
Thank you, Marco!
next prev parent reply other threads:[~2023-07-05 13:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-05 12:44 andrey.konovalov
2023-07-05 12:50 ` Marco Elver
2023-07-05 13:19 ` Andrey Konovalov [this message]
2023-07-06 9:03 ` Will Deacon
2023-07-10 9:53 ` Vlastimil Babka
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