Re: [PATCH] libnvdimm/of_pmem: Add check and kfree for kstrdup

From: Jiasheng Jiang
Date: Thu Jun 22 2023 - 10:38:16 EST


On Wed, Jun 21, 2023 at 00:04:36 +0800, Ira Weiny wrote:
> Ira Weiny wrote:
>> Jiasheng Jiang wrote:
>> > Add check for the return value of kstrdup() and return the error
>> > if it fails in order to avoid NULL pointer dereference.
>> > Moreover, use kfree() in the later error handling in order to avoid
>> > memory leak.
>> >
>> > Fixes: 49bddc73d15c ("libnvdimm/of_pmem: Provide a unique name for bus provider")
>> > Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
>> > ---
>> > drivers/nvdimm/of_pmem.c | 6 ++++++
>> > 1 file changed, 6 insertions(+)
>> >
>> > diff --git a/drivers/nvdimm/of_pmem.c b/drivers/nvdimm/of_pmem.c
>> > index 10dbdcdfb9ce..fe6edb7e6631 100644
>> > --- a/drivers/nvdimm/of_pmem.c
>> > +++ b/drivers/nvdimm/of_pmem.c
>> > @@ -31,11 +31,17 @@ static int of_pmem_region_probe(struct platform_device *pdev)
>> > return -ENOMEM;
>> >
>> > priv->bus_desc.provider_name = kstrdup(pdev->name, GFP_KERNEL);
>> > + if (!priv->bus_desc.provider_name) {
>> > + kfree(priv);
>> > + return -ENOMEM;
>> > + }
>> > +
>> > priv->bus_desc.module = THIS_MODULE;
>> > priv->bus_desc.of_node = np;
>> >
>> > priv->bus = bus = nvdimm_bus_register(&pdev->dev, &priv->bus_desc);
>> > if (!bus) {
>> > + kfree(priv->bus_desc.provider_name);
>>
>> Nice catch!
>>
>> However, this free needs to happen in of_pmem_region_remove() as well.
>
> Looks like the mail from my phone had html in it. Sorry for that.
>
> This would be better with devm_kstrdup() and then we don't have to worry
> about the kfree at all.

Looks good.
I have submitted a new patch "libnvdimm/of_pmem: Replace kstrdup with devm_kstrdup and add check".
Since the titie has been modified, I did not submitted a v2.

- Jiasheng Jiang