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

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Date:   Mon, 8 Nov 2021 08:14:16 -0800
From:   Ira Weiny <ira.weiny@...el.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
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()'

On Sun, Nov 07, 2021 at 06:20:14PM +0100, Christophe JAILLET wrote:
> 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.

Ah I see.  Sorry.

> 
> 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.
>

Yes agreed.  I was looking at Linus' kernel not linux-next sorry.

Sorry for the noise,
Ira

> 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
> > > 
> > 
>