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From: Ben Widawsky <ben.widawsky@intel.com>
To: Al Viro <viro@zeniv.linux.org.uk>
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>,
	David Hildenbrand <david@redhat.com>,
	David Rientjes <rientjes@google.com>,
	Jon Masters <jcm@jonmasters.org>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	"John Groves (jgroves)" <jgroves@micron.com>,
	"Kelley, Sean V" <sean.v.kelley@intel.com>,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v4 4/9] cxl/mem: Add basic IOCTL interface
Date: Tue, 16 Feb 2021 10:22:32 -0800	[thread overview]
Message-ID: <20210216182232.mmo5pwchongpmrau@intel.com> (raw)
In-Reply-To: <YCwK9SblYCh/1lZS@zeniv-ca.linux.org.uk>

On 21-02-16 18:12:05, Al Viro wrote:
> On Mon, Feb 15, 2021 at 05:45:33PM -0800, Ben Widawsky wrote:
> > +	if (cmd->info.size_in) {
> > +		mbox_cmd.payload_in = kvzalloc(cmd->info.size_in, GFP_KERNEL);
> > +		if (!mbox_cmd.payload_in) {
> > +			rc = -ENOMEM;
> > +			goto out;
> > +		}
> > +
> > +		if (copy_from_user(mbox_cmd.payload_in,
> > +				   u64_to_user_ptr(in_payload),
> > +				   cmd->info.size_in)) {
> > +			rc = -EFAULT;
> > +			goto out;
> > +		}
> 
> Umm...  Do you need to open-code vmemdup_user()?  The only difference is
> GFP_KERNEL allocation instead of GFP_USER one, and the latter is arguably
> saner here...  Zeroing is definitely pointless - you either overwrite
> the entire buffer with copy_from_user(), or you fail and free the damn
> thing.

mea culpa. In fact it was previously memdup_user and Dan suggested I switch to
vmemdup_user.
https://lore.kernel.org/linux-cxl/CAPcyv4j+ixVgEo5q2OhV4kdkBZbnohZj3KDovReQJjPBsREugw@mail.gmail.com/


Will fix for the next version.

Thanks.
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WARNING: multiple messages have this Message-ID (diff)
From: Ben Widawsky <ben.widawsky@intel.com>
To: Al Viro <viro@zeniv.linux.org.uk>
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>
Subject: Re: [PATCH v4 4/9] cxl/mem: Add basic IOCTL interface
Date: Tue, 16 Feb 2021 10:22:32 -0800	[thread overview]
Message-ID: <20210216182232.mmo5pwchongpmrau@intel.com> (raw)
In-Reply-To: <YCwK9SblYCh/1lZS@zeniv-ca.linux.org.uk>

On 21-02-16 18:12:05, Al Viro wrote:
> On Mon, Feb 15, 2021 at 05:45:33PM -0800, Ben Widawsky wrote:
> > +	if (cmd->info.size_in) {
> > +		mbox_cmd.payload_in = kvzalloc(cmd->info.size_in, GFP_KERNEL);
> > +		if (!mbox_cmd.payload_in) {
> > +			rc = -ENOMEM;
> > +			goto out;
> > +		}
> > +
> > +		if (copy_from_user(mbox_cmd.payload_in,
> > +				   u64_to_user_ptr(in_payload),
> > +				   cmd->info.size_in)) {
> > +			rc = -EFAULT;
> > +			goto out;
> > +		}
> 
> Umm...  Do you need to open-code vmemdup_user()?  The only difference is
> GFP_KERNEL allocation instead of GFP_USER one, and the latter is arguably
> saner here...  Zeroing is definitely pointless - you either overwrite
> the entire buffer with copy_from_user(), or you fail and free the damn
> thing.

mea culpa. In fact it was previously memdup_user and Dan suggested I switch to
vmemdup_user.
https://lore.kernel.org/linux-cxl/CAPcyv4j+ixVgEo5q2OhV4kdkBZbnohZj3KDovReQJjPBsREugw@mail.gmail.com/


Will fix for the next version.

Thanks.

  reply	other threads:[~2021-02-17  1:36 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-16  1:45 [PATCH v4 0/9] CXL 2.0 Support Ben Widawsky
2021-02-16  1:45 ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 2/9] cxl/mem: Find device capabilities Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16 14:51   ` Jonathan Cameron
2021-02-16 14:51     ` Jonathan Cameron
2021-02-16 16:43     ` Ben Widawsky
2021-02-16 16:43       ` Ben Widawsky
2021-02-16 17:20       ` Jonathan Cameron
2021-02-16 17:20         ` Jonathan Cameron
2021-02-16 17:56         ` Ben Widawsky
2021-02-16 17:56           ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 4/9] cxl/mem: Add basic IOCTL interface Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16 15:22   ` Jonathan Cameron
2021-02-16 15:22     ` Jonathan Cameron
2021-02-16 17:53     ` Ben Widawsky
2021-02-16 17:53       ` Ben Widawsky
2021-02-16 18:28       ` Jonathan Cameron
2021-02-16 18:28         ` Jonathan Cameron
2021-02-16 18:34         ` Ben Widawsky
2021-02-16 18:34           ` Ben Widawsky
2021-02-17  9:55           ` Jonathan Cameron
2021-02-17  9:55             ` Jonathan Cameron
2021-02-16 18:12   ` Al Viro
2021-02-16 18:12     ` Al Viro
2021-02-16 18:22     ` Ben Widawsky [this message]
2021-02-16 18:22       ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 5/9] cxl/mem: Add a "RAW" send command Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16 15:30   ` Jonathan Cameron
2021-02-16 15:30     ` Jonathan Cameron
2021-02-16 18:03     ` Ben Widawsky
2021-02-16 18:03       ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16 15:43   ` Jonathan Cameron
2021-02-16 15:43     ` Jonathan Cameron
2021-02-16  1:45 ` [PATCH v4 7/9] cxl/mem: Add set of informational commands Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 8/9] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16  1:45 ` [PATCH v4 9/9] cxl/mem: Add payload dumping for debug Ben Widawsky
2021-02-16  1:45   ` Ben Widawsky
2021-02-16 15:48   ` Jonathan Cameron
2021-02-16 15:48     ` Jonathan Cameron
2021-02-16 16:48     ` Dan Williams
2021-02-16 16:48       ` Dan Williams

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