linux-kernel - Re: [PATCH] cxl/region: Fix memregion leaks in devm_cxl_add

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Date: Tue, 7 May 2024 08:52:53 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: "Zhijian Li (Fujitsu)" <lizhijian@...itsu.com>,
 Ira Weiny <ira.weiny@...el.com>, "dave@...olabs.net" <dave@...olabs.net>,
 "jonathan.cameron@...wei.com" <jonathan.cameron@...wei.com>,
 "alison.schofield@...el.com" <alison.schofield@...el.com>,
 "vishal.l.verma@...el.com" <vishal.l.verma@...el.com>,
 "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
 "linux-cxl@...r.kernel.org" <linux-cxl@...r.kernel.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cxl/region: Fix memregion leaks in devm_cxl_add_region()



On 5/6/24 7:42 PM, Zhijian Li (Fujitsu) wrote:
> 
> 
> On 30/04/2024 00:23, Ira Weiny wrote:
>> Li Zhijian wrote:
>>> Move memregion_free(id) out of cxl_region_alloc() and
>>> explicately free memregion in devm_cxl_add_region() error path.
>>    ^^^^
>>    explicitly
>>
>> BTW you should run checkpatch.pl which will check spelling.
> 
> 
> I remember I've done this check, but it seems the it doesn't work for me.
> Did I miss something?
> 
> $ ./scripts/checkpatch.pl 0001-cxl-region-Fix-memregion-leaks-in-devm_cxl_add_regio.patch
> total: 0 errors, 0 warnings, 23 lines checked
> 
> 0001-cxl-region-Fix-memregion-leaks-in-devm_cxl_add_regio.patch has no obvious style problems and is ready for submission.

Pass in --codespell parameter. And make sure you have the codespell dictionary installed (i.e. /usr/share/codespell/dictionary.txt). 

DJ

> 
> 
> 
>>
>> I'm not following what the problem is you are trying to fix.  This seems
>> like it just moves the memregion_free() around a bit but the logic is the
>> same.
>>
> 
> Sorry, I think my commit log may be misleading. In fact, this patch mainly fixes
> the memregion leak in devm_cxl_add_region() when it gets an invalid mode.
> 
>>>   	default:
>>>   		dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
>>> +		memregion_free(id);
>>>   		return ERR_PTR(-EINVAL);
>>>   	}
> 
> Additionally, to maintain consistent error handling, I also moved memregion_free(id) from
> cxl_region_alloc() to devm_cxl_add_region() so that devm_cxl_add_region() can
> free memregion explicitly in error path.
> 
> 
> Thanks
> Zhijian
> 
> 
>> Ira
>>
>>>
>>> After cxl_region_alloc() succeed, memregion will be freed by
>>> cxl_region_type.release()
>>>
>>> Fixes: 6e099264185d ("cxl/region: Add volatile region creation support")
>>> Signed-off-by: Li Zhijian <lizhijian@...itsu.com>
>>> ---
>>>   drivers/cxl/core/region.c | 9 +++++----
>>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>>> index 812b2948b6c6..8535718a20f0 100644
>>> --- a/drivers/cxl/core/region.c
>>> +++ b/drivers/cxl/core/region.c
>>> @@ -2250,10 +2250,8 @@ static struct cxl_region *cxl_region_alloc(struct cxl_root_decoder *cxlrd, int i
>>>   	struct device *dev;
>>>   
>>>   	cxlr = kzalloc(sizeof(*cxlr), GFP_KERNEL);
>>> -	if (!cxlr) {
>>> -		memregion_free(id);
>>> +	if (!cxlr)
>>>   		return ERR_PTR(-ENOMEM);
>>> -	}
>>>   
>>>   	dev = &cxlr->dev;
>>>   	device_initialize(dev);
>>> @@ -2358,12 +2356,15 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
>>>   		break;
>>>   	default:
>>>   		dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
>>> +		memregion_free(id);
>>>   		return ERR_PTR(-EINVAL);
>>>   	}
>>>   
>>>   	cxlr = cxl_region_alloc(cxlrd, id);
>>> -	if (IS_ERR(cxlr))
>>> +	if (IS_ERR(cxlr)) {
>>> +		memregion_free(id);
>>>   		return cxlr;
>>> +	}
>>>   	cxlr->mode = mode;
>>>   	cxlr->type = type;
>>>   
>>> -- 
>>> 2.29.2
>>>
>>
>>