Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Sun, 14 May 2023 23:08:11 +0800
From:   Ruihan Li <lrh2000@pku.edu.cn>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Christoph Hellwig <hch@infradead.org>, linux-mm@kvack.org,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        David Hildenbrand <david@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ruihan Li <lrh2000@pku.edu.cn>
Subject: Re: [PATCH 0/4] Fix type confusion in page_table_check
Message-ID: <zwcena7ynuhyqqioppeh47jdlgvkc5k2uar3cnvkgwzck4w7w3@riv4ca62kyjr>
References: <20230510085527.57953-1-lrh2000@pku.edu.cn>
 <2023051108-lens-unsocial-8425@gregkh>
 <cyym2uqyqdtegfbdpworng4fa7iiuyh3e2wjrf4lp47jksvoxt@wwhvnzy5757c>
 <ZF0KcRgclDJ6POrb@infradead.org>
 <zwixiok55avpjvfiknp7tzm7e4aragjj43a46abna4qqegdvdx@suat6sk34lgb>
 <2023051324-attentive-footwork-9dec@gregkh>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <2023051324-attentive-footwork-9dec@gregkh>
Precedence: bulk

On Sat, May 13, 2023 at 06:37:52PM +0900, Greg Kroah-Hartman wrote:
> 
> On Fri, May 12, 2023 at 12:19:09AM +0800, Ruihan Li wrote:
> > On Thu, May 11, 2023 at 08:32:01AM -0700, Christoph Hellwig wrote:
> > > On Thu, May 11, 2023 at 09:44:55PM +0800, Ruihan Li wrote:
> > > > Christoph's patch perfectly fixes _one_ problem: kmalloc'ed memory
> > > > cannot be mapped to user space. However, as I detailed in the commit
> > > > message, this series of patches fixes _three_ problems.
> > > 
> > > FYI, I agree with you.  My simple patch was sent before reading
> > > your new series, and is a strict subset of it.
> > 
> > Thank you for the clarification.
> > 
> > > > I have to say that the original code is quite buggy. In the
> > > > gen_pool_dma_alloc path, there is no guarantee of page alignment. 
> > > 
> > > I also find this whole interface very problematic to start with,
> > > but that's a separate discussion for later.
> > 
> > Yes. I don't think hybrid allocation of DMA memory and normal memory in
> > one function is a good thing, but currently there is no clear way to fix
> > this. Mixing memory allocation and page allocation is another bad thing,
> > and at least, my patch can (hopefully) solve the second (and much
> > easier) issue.
> 
> Ok, I'll take these through the usb tree if I can get an ack for the
> mm-specific patches.  Or were you going to send a v2 series?
> 
> thanks,
> 
> greg k-h

There are some comments from Alan and David, so I'll send a v2 series to
address them (probably tomorrow).

Thanks,
Ruihan Li