Messages in this thread | | | From | Dan Williams <> | Date | Tue, 26 Mar 2019 11:31:51 -0700 | Subject | Re: [PATCH v4] nvdimm: btt_devs: fix a NULL pointer dereference |
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On Tue, Mar 26, 2019 at 3:23 AM Mukesh Ojha <mojha@codeaurora.org> wrote: > > > On 3/26/2019 3:25 AM, Aditya Pakki wrote: > > In case kmemdup fails, the fix releases resources and returns to > > avoid the NULL pointer dereference. > > > > Signed-off-by: Aditya Pakki <pakki001@umn.edu> > > > > --- > > v3: Move kfree(nd_btt) to goto block. > > v2: Replace incorrect kfree with ida_simple_remove, suggested by > > Johannes Thumshirn > > v1: Free nd_btt->id in case of failure and avoid double free, suggested > > by Dan Williams > > --- > > drivers/nvdimm/btt_devs.c | 18 +++++++++++++----- > > 1 file changed, 13 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c > > index b72a303176c7..9486acc08402 100644 > > --- a/drivers/nvdimm/btt_devs.c > > +++ b/drivers/nvdimm/btt_devs.c > > @@ -198,14 +198,15 @@ static struct device *__nd_btt_create(struct nd_region *nd_region, > > return NULL; > > > > nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL); > > - if (nd_btt->id < 0) { > > - kfree(nd_btt); > > - return NULL; > > - } > > + if (nd_btt->id < 0) > > + goto out_nd_btt; > > > > nd_btt->lbasize = lbasize; > > - if (uuid) > > + if (uuid) { > > uuid = kmemdup(uuid, 16, GFP_KERNEL); > > + if (!uuid) > > + goto out_put_id; > > + } > > nd_btt->uuid = uuid; > > dev = &nd_btt->dev; > > dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id); > > @@ -220,6 +221,13 @@ static struct device *__nd_btt_create(struct nd_region *nd_region, > > return NULL; > > } > > return dev; > > + > > +out_put_id: > > + ida_simple_remove(&nd_region->btt_ida, nd_btt->id); > > + > > +out_nd_btt: > > + kfree(nd_btt); > > + return NULL; > > } > > > > struct device *nd_btt_create(struct nd_region *nd_region) > > > you have to take care of this below if block(true) as well as you are > touching the function. > if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
No, once the device is successfully initialized then put_device() takes care of the rest.
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