From: Dan Carpenter <dan.carpenter@linaro.org>
To: "Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com>
Cc: "dave@stgolabs.net" <dave@stgolabs.net>,
"jonathan.cameron@huawei.com" <jonathan.cameron@huawei.com>,
"dave.jiang@intel.com" <dave.jiang@intel.com>,
"alison.schofield@intel.com" <alison.schofield@intel.com>,
"vishal.l.verma@intel.com" <vishal.l.verma@intel.com>,
"ira.weiny@intel.com" <ira.weiny@intel.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] cxl/region: Fix potential invalid pointer dereference
Date: Mon, 29 Apr 2024 13:30:28 +0300 [thread overview]
Message-ID: <c6cab703-87df-4152-a5b0-a0ce31e7f057@moroto.mountain> (raw)
In-Reply-To: <576dccd9-1f8d-4c69-bc7f-497413b87b9d@fujitsu.com>
On Mon, Apr 29, 2024 at 10:25:35AM +0000, Zhijian Li (Fujitsu) wrote:
> > 3084 mutex_lock(&cxlrd->range_lock);
> > 3085 region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
> > 3086 match_region_by_range);
> > 3087 if (!region_dev) {
> > 3088 cxlr = construct_region(cxlrd, cxled);
> > 3089 region_dev = &cxlr->dev;
> > ^^^^^^^^^^^
> > This is not a dereference, it's just pointer math. In in this case it's
> > the same as saying:
> >
> > region_dev = (void *)cxlr;
>
>
> You are right, a equivalent code could be:
> region_dev = ((char *)cxlr) + offsetof(struct cxl_region, dev);
>
>
Correct. But offsetof() is zero. It's the same math that to_cxl_region()
does.
regards,
dan carpenter
next prev parent reply other threads:[~2024-04-29 10:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 1:31 [PATCH 1/2] cxl/region: Fix potential invalid pointer dereference Li Zhijian
2024-04-29 1:31 ` [PATCH 2/2] cxl/region: Fix missing put_device(region_dev) Li Zhijian
2024-04-29 1:51 ` Zhijian Li (Fujitsu)
2024-04-29 8:00 ` Markus Elfring
2024-04-29 8:26 ` Zhijian Li (Fujitsu)
2024-04-29 10:00 ` Dan Carpenter
2024-04-29 10:11 ` Zhijian Li (Fujitsu)
2024-04-29 8:35 ` Zhijian Li (Fujitsu)
2024-04-29 10:17 ` Dan Carpenter
2024-04-29 10:26 ` Zhijian Li (Fujitsu)
2024-04-29 10:32 ` Dan Carpenter
2024-04-29 16:14 ` Ira Weiny
2024-04-29 7:50 ` [PATCH 1/2] cxl/region: Fix potential invalid pointer dereference Markus Elfring
2024-04-29 8:43 ` Zhijian Li (Fujitsu)
2024-04-29 8:55 ` [1/2] " Markus Elfring
2024-04-29 10:10 ` [PATCH 1/2] " Dan Carpenter
2024-04-29 10:25 ` Zhijian Li (Fujitsu)
2024-04-29 10:30 ` Dan Carpenter [this message]
2024-04-29 16:17 ` Ira Weiny
2024-04-29 16:05 ` Ira Weiny
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