Date:   Thu, 26 Jan 2023 12:28:49 +0100 (CET)
From:   Christoph Lameter <cl@gentwo.de>
To:     George Prekas <george@enfabrica.net>
cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        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>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Andrei Vagin <avagin@gmail.com>
Subject: Re: [PATCH 7/9] mm: kmemleak: erase page->s_mem in slab_destroy
In-Reply-To: <20230123170419.7292-8-george@enfabrica.net>
Message-ID: <73309bf-ca5b-b0ba-8ac-4be7dcc278b7@gentwo.de>
References: <20230123170419.7292-1-george@enfabrica.net> <20230123170419.7292-8-george@enfabrica.net>
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On Mon, 23 Jan 2023, George Prekas wrote:

> The field s_mem of struct page is initialized with the virtual address
> of the page in function alloc_slabmgmt. If kmalloc allocates an object
> that starts on this page, then kmemleak knows that this object has 2
> references. On slab_destroy, s_mem should not continue referring to any
> allocated object in the future.

Nope.

s_mem is a pointer to an array of objects. It is not a pointer to a page.

If a slab-caches is used for slabmanagement then these objects
contain slab metadata which may be a bit confusing.