From: "Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com>
To: "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>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] cxl/region: Fix missing put_device(region_dev)
Date: Mon, 29 Apr 2024 01:51:33 +0000 [thread overview]
Message-ID: <db8619ed-8c64-4494-8552-1c54f1c189e6@fujitsu.com> (raw)
In-Reply-To: <20240429013154.368118-2-lizhijian@fujitsu.com>
On 29/04/2024 09:31, Li Zhijian wrote:
>> mutex_lock(&cxlrd->range_lock);
>> region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
>> match_region_by_range);
>> if (!region_dev)
>> cxlr = construct_region(cxlrd, cxled);
>> else
>> cxlr = to_cxl_region(region_dev);
>> mutex_unlock(&cxlrd->range_lock);
>>
>> rc = PTR_ERR_OR_ZERO(cxlr);
Think again, PTR_ERR_OR_ZERO() here should be IS_ERR_OR_NULL()?
PTR_ERR_OR_ZERO() returns 0 if cxlr is NULL, but the cxlr will be dereferenced later.
>> if (rc)
>> goto out;
>>
>> if (!region_dev)
>> region_dev = &cxlr->dev;
>
> When to_cxl_region(region_dev) fails, put_device(region_dev) should be
> called to decrease the reference count added by device_find_child().
>
> Simply put_device(region_dev) if region_dev is valid in the error path.
>
> Fixes: a32320b71f08 ("cxl/region: Add region autodiscovery")
> Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
> ---
> drivers/cxl/core/region.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 3c80aa263a65..75390865382f 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3117,8 +3117,9 @@ int cxl_add_to_region(struct cxl_port *root, struct cxl_endpoint_decoder *cxled)
> p->res);
> }
>
> - put_device(region_dev);
> out:
> + if (region_dev)
> + put_device(region_dev);
> put_device(cxlrd_dev);
> return rc;
> }
next prev parent reply other threads:[~2024-04-29 1:52 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) [this message]
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
2024-04-29 16:17 ` Ira Weiny
2024-04-29 16:05 ` Ira Weiny
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