Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200701151645.GA26223@lilong>
In-Reply-To: <20200701151645.GA26223@lilong>
From:   Pekka Enberg <penberg@gmail.com>
Date:   Wed, 1 Jul 2020 18:47:49 +0300
Message-ID: <CAOJsxLGST_hgA3OPOdxQpZH_fX5m--WE2Wf8DfTLd557NUD5hQ@mail.gmail.com>
Subject: Re: [PATCH v3] mm, slab: Check GFP_SLAB_BUG_MASK before alloc_pages
 in kmalloc_order
To:     Long Li <lonuxli.64@gmail.com>
Cc:     willy@infradead.org, Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Jul 1, 2020 at 6:19 PM Long Li <lonuxli.64@gmail.com> wrote:
>
> kmalloc cannot allocate memory from HIGHMEM.  Allocating large amounts
> of memory currently bypasses the check and will simply leak the memory
> when page_address() returns NULL.  To fix this, factor the
> GFP_SLAB_BUG_MASK check out of slab & slub, and call it from
> kmalloc_order() as well. In order to make the code clear, the warning
> message is put in one place.
>
> Signed-off-by: Long Li <lonuxli.64@gmail.com>

Reviewed-by: Pekka Enberg <penberg@kernel.org>