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Date:   Sun, 14 Feb 2021 23:57:58 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Ben Widawsky <ben.widawsky@intel.com>
Cc:     linux-cxl@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
        linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
        Chris Browy <cbrowy@avery-design.com>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        David Hildenbrand <david@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Jon Masters <jcm@jonmasters.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        "John Groves (jgroves)" <jgroves@micron.com>,
        "Kelley, Sean V" <sean.v.kelley@intel.com>,
        kernel test robot <lkp@intel.com>,
        Dan Williams <dan.j.willams@intel.com>
Subject: Re: [PATCH v2 4/8] cxl/mem: Add basic IOCTL interface
Message-ID: <YCm5Bs2NalmHgeZn@zeniv-ca.linux.org.uk>
References: <20210210000259.635748-1-ben.widawsky@intel.com>
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 <YClQEefYBR+YKBUv@zeniv-ca.linux.org.uk>
 <20210214231456.xnwitliczv6qwmjv@intel.com>
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Sender: Al Viro <viro@ftp.linux.org.uk>
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On Sun, Feb 14, 2021 at 11:50:12PM +0000, Al Viro wrote:
> 	check that len is reasonable
> 	p = kmalloc(offsetof(struct foo, string[len]), GFP_KERNEL);
> 	copy_from_user(p, user_object, len);
			offsetof(struct foo, string[len]), that is