From: Marco Elver <elver@google.com>
To: Jann Horn <jannh@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andrew Morton <akpm@linux-foundation.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>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v5 2/2] slub: Introduce CONFIG_SLUB_RCU_DEBUG
Date: Fri, 2 Aug 2024 10:06:30 +0200 [thread overview]
Message-ID: <ZqyThs-o85nqueaF@elver.google.com> (raw)
In-Reply-To: <20240730-kasan-tsbrcu-v5-2-48d3cbdfccc5@google.com>
On Tue, Jul 30, 2024 at 01:06PM +0200, Jann Horn wrote:
[...]
> +#ifdef CONFIG_SLUB_RCU_DEBUG
> + if ((s->flags & SLAB_TYPESAFE_BY_RCU) && !after_rcu_delay) {
> + struct rcu_delayed_free *delayed_free;
> +
> + delayed_free = kmalloc(sizeof(*delayed_free), GFP_NOWAIT);
This may well be allocated by KFENCE.
[...]
> +#ifdef CONFIG_SLUB_RCU_DEBUG
> +static void slab_free_after_rcu_debug(struct rcu_head *rcu_head)
> +{
> + struct rcu_delayed_free *delayed_free =
> + container_of(rcu_head, struct rcu_delayed_free, head);
> + void *object = delayed_free->object;
> + struct slab *slab = virt_to_slab(object);
> + struct kmem_cache *s;
> +
> + if (WARN_ON(is_kfence_address(rcu_head)))
> + return;
syzbot found this warning to trigger (because see above comment):
https://lore.kernel.org/all/00000000000052aa15061eaeb1fd@google.com/
Should this have been `is_kfence_address(object)`?
next prev parent reply other threads:[~2024-08-02 8:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-30 11:06 [PATCH v5 0/2] allow KASAN to detect UAF in SLAB_TYPESAFE_BY_RCU slabs Jann Horn
2024-07-30 11:06 ` [PATCH v5 1/2] kasan: catch invalid free before SLUB reinitializes the object Jann Horn
2024-08-01 0:22 ` Andrey Konovalov
2024-08-01 4:00 ` Jann Horn
2024-08-01 12:54 ` Andrey Konovalov
2024-08-02 11:05 ` Jann Horn
2024-08-02 9:56 ` Jann Horn
2024-08-02 19:35 ` Andrey Konovalov
2024-07-30 11:06 ` [PATCH v5 2/2] slub: Introduce CONFIG_SLUB_RCU_DEBUG Jann Horn
2024-07-30 11:30 ` Vlastimil Babka
2024-08-01 0:23 ` Andrey Konovalov
2024-08-02 9:09 ` Jann Horn
2024-08-02 11:22 ` Jann Horn
2024-08-02 19:35 ` Andrey Konovalov
2024-08-02 8:06 ` Marco Elver [this message]
2024-08-02 8:16 ` Jann Horn
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