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

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Date:   Sun, 7 Nov 2021 18:25:15 +0100
From:   Marion & 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 18:20, Christophe JAILLET a écrit :
> 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 
> 

Lol, the #n512 above is in fact another place that should be updated as 
well. I missed it and only fixed #n494!

CJ

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