* [PATCH] device-dax: fix cdev leak
@ 2017-02-23 19:22 Dan Williams
2017-02-23 20:20 ` Jason Gunthorpe
0 siblings, 1 reply; 3+ messages in thread
From: Dan Williams @ 2017-02-23 19:22 UTC (permalink / raw)
To: linux-nvdimm; +Cc: Jason Gunthorpe, Logan Gunthorpe, linux-kernel, stable
If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
with a stale device number.
Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
Cc: <stable@vger.kernel.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dax/dax.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index ed758b74ddf0..0f8008dd0b0c 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
rc = device_add(dev);
if (rc) {
+ cdev_del(&dax_dev->cdev);
put_device(dev);
return ERR_PTR(rc);
}
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] device-dax: fix cdev leak
2017-02-23 19:22 [PATCH] device-dax: fix cdev leak Dan Williams
@ 2017-02-23 20:20 ` Jason Gunthorpe
2017-02-23 20:27 ` Dan Williams
0 siblings, 1 reply; 3+ messages in thread
From: Jason Gunthorpe @ 2017-02-23 20:20 UTC (permalink / raw)
To: Dan Williams; +Cc: linux-nvdimm, Logan Gunthorpe, linux-kernel, stable
On Thu, Feb 23, 2017 at 11:22:03AM -0800, Dan Williams wrote:
> If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
> with a stale device number.
>
> Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
> Cc: <stable@vger.kernel.org>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> drivers/dax/dax.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
> index ed758b74ddf0..0f8008dd0b0c 100644
> +++ b/drivers/dax/dax.c
> @@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
> dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
> rc = device_add(dev);
> if (rc) {
> + cdev_del(&dax_dev->cdev);
This probably should call into unregister_dax_dev and just skip the
device_unregister part.
Once cdev_add returns it is possible for a mmap to have been created,
so cleanup after that point has to go through all the other
unregister_dax_dev steps.
Jason
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] device-dax: fix cdev leak
2017-02-23 20:20 ` Jason Gunthorpe
@ 2017-02-23 20:27 ` Dan Williams
0 siblings, 0 replies; 3+ messages in thread
From: Dan Williams @ 2017-02-23 20:27 UTC (permalink / raw)
To: Jason Gunthorpe; +Cc: linux-nvdimm, Logan Gunthorpe, linux-kernel, stable
On Thu, Feb 23, 2017 at 12:20 PM, Jason Gunthorpe
<jgunthorpe@obsidianresearch.com> wrote:
> On Thu, Feb 23, 2017 at 11:22:03AM -0800, Dan Williams wrote:
>> If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
>> with a stale device number.
>>
>> Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
>> Cc: <stable@vger.kernel.org>
>> Cc: Logan Gunthorpe <logang@deltatee.com>
>> Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>> drivers/dax/dax.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
>> index ed758b74ddf0..0f8008dd0b0c 100644
>> +++ b/drivers/dax/dax.c
>> @@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
>> dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
>> rc = device_add(dev);
>> if (rc) {
>> + cdev_del(&dax_dev->cdev);
>
> This probably should call into unregister_dax_dev and just skip the
> device_unregister part.
>
> Once cdev_add returns it is possible for a mmap to have been created,
> so cleanup after that point has to go through all the other
> unregister_dax_dev steps.
Ah true. I was thinking the device node is not auto-created if the
device_add() fails, but there's theoretically nothing stopping
userspace from trying to hit this race with its own self-created
device-node.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-02-23 20:29 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2017-02-23 19:22 [PATCH] device-dax: fix cdev leak Dan Williams
2017-02-23 20:20 ` Jason Gunthorpe
2017-02-23 20:27 ` Dan Williams
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