linux-kernel - Re: [PATCH] nvdimm/pmem: Fix an error handling path in 'pmem_attach

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Date:   Sun, 7 Nov 2021 18:20:14 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Ira Weiny <ira.weiny@...el.com>
Cc:     dan.j.williams@...el.com, vishal.l.verma@...el.com,
        dave.jiang@...el.com, nvdimm@...ts.linux.dev,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] nvdimm/pmem: Fix an error handling path in
 'pmem_attach_disk()'

Le 07/11/2021 à 18:11, Ira Weiny a écrit :
> On Sat, Nov 06, 2021 at 06:27:11PM +0100, Christophe JAILLET wrote:
>> If 'devm_init_badblocks()' fails, a previous 'blk_alloc_disk()' call must
>> be undone.
> 
> I think this is a problem...
> 
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>> ---
>> This patch is speculative. Several fixes on error handling paths have been
>> done recently, but this one has been left as-is. There was maybe a good
>> reason that I have missed for that. So review with care!
>>
>> I've not been able to identify a Fixes tag that please me :(
>> ---
>>   drivers/nvdimm/pmem.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
>> index fe7ece1534e1..c37a1e6750b3 100644
>> --- a/drivers/nvdimm/pmem.c
>> +++ b/drivers/nvdimm/pmem.c
>> @@ -490,8 +490,9 @@ static int pmem_attach_disk(struct device *dev,
>>   	nvdimm_namespace_disk_name(ndns, disk->disk_name);
>>   	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
>>   			/ 512);
>> -	if (devm_init_badblocks(dev, &pmem->bb))
>> -		return -ENOMEM;
>> +	rc = devm_init_badblocks(dev, &pmem->bb);
>> +	if (rc)
>> +		goto out;
> 
> But I don't see this 'out' label in the function currently?  Was that part of
> your patch missing?

Hi,
the patch is based on the latest linux-next.
See [1]. The 'out' label exists there and is already used.

In fact, I run an own-made coccinelle script which tries to spot mix-up 
between return and goto.
In this case, we have a 'return -ENOMEM' after a 'goto out' which looks 
spurious. Hence, my patch.

[1]:https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/nvdimm/pmem.c#n512

CJ

> 
> Ira
> 
>>   	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range);
>>   	disk->bb = &pmem->bb;
>>   
>> -- 
>> 2.30.2
>>
>