2022-01-26 19:51:48

by Miaoqian Lin

[permalink] [raw]
Subject: [PATCH] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

kobject_init_and_add() takes reference even when it fails.
According to the doc of kobject_init_and_add():

If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object.

Fix memory leak by calling kobject_put().

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Signed-off-by: Miaoqian Lin <[email protected]>
---
drivers/hv/vmbus_drv.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55fe3169..9e055697783b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
kobj->kset = dev->channels_kset;
ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
"%u", relid);
- if (ret)
+ if (ret) {
+ kobject_put(kobj);
return ret;
+ }

ret = sysfs_create_group(kobj, &vmbus_chan_group);

--
2.17.1


2022-01-31 11:46:03

by Juan Vazquez

[permalink] [raw]
Subject: Re: [PATCH] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

On Wed, Jan 26, 2022 at 05:52:46AM +0000, Miaoqian Lin wrote:
> kobject_init_and_add() takes reference even when it fails.
> According to the doc of kobject_init_and_add():
>
> If this function returns an error, kobject_put() must be called to
> properly clean up the memory associated with the object.
>
> Fix memory leak by calling kobject_put().
>
> Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> drivers/hv/vmbus_drv.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 17bf55fe3169..9e055697783b 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
> kobj->kset = dev->channels_kset;
> ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
> "%u", relid);
> - if (ret)
> + if (ret) {
> + kobject_put(kobj);
> return ret;
> + }
>
> ret = sysfs_create_group(kobj, &vmbus_chan_group);
If sysfs_create_group() fails same cleanup I think is required.

Later kobject_uevent() may fail according to doc, but there is no error
handling, maybe a good moment to consider adding it and do same cleanup.
>
> --
> 2.17.1

2022-02-03 15:37:44

by Wei Liu

[permalink] [raw]
Subject: Re: [PATCH] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

On Fri, Jan 28, 2022 at 01:56:04PM -0800, Juan Vazquez wrote:
> On Wed, Jan 26, 2022 at 05:52:46AM +0000, Miaoqian Lin wrote:
> > kobject_init_and_add() takes reference even when it fails.
> > According to the doc of kobject_init_and_add():
> >
> > If this function returns an error, kobject_put() must be called to
> > properly clean up the memory associated with the object.
> >
> > Fix memory leak by calling kobject_put().
> >
> > Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
> > Signed-off-by: Miaoqian Lin <[email protected]>
> > ---
> > drivers/hv/vmbus_drv.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> > index 17bf55fe3169..9e055697783b 100644
> > --- a/drivers/hv/vmbus_drv.c
> > +++ b/drivers/hv/vmbus_drv.c
> > @@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
> > kobj->kset = dev->channels_kset;
> > ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
> > "%u", relid);
> > - if (ret)
> > + if (ret) {
> > + kobject_put(kobj);
> > return ret;
> > + }
> >
> > ret = sysfs_create_group(kobj, &vmbus_chan_group);
> If sysfs_create_group() fails same cleanup I think is required.
>
> Later kobject_uevent() may fail according to doc, but there is no error
> handling, maybe a good moment to consider adding it and do same cleanup.

Miaoqian, are you going to post a new version to address Juan's comment
here?

Thanks,
Wei.

> >
> > --
> > 2.17.1

2022-02-03 19:06:16

by Miaoqian Lin

[permalink] [raw]
Subject: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

kobject_init_and_add() takes reference even when it fails.
According to the doc of kobject_init_and_add():

If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object.

Fix memory leak by calling kobject_put().

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Signed-off-by: Miaoqian Lin <[email protected]>
---
Changes in v2:
- Add cleanup when sysfs_create_group() fails

kobject_uevent() is used for notifying userspace by sending an uevent,
I don't think we need to do error handling for it.
---
drivers/hv/vmbus_drv.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55fe3169..34a4fd21bdf5 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
kobj->kset = dev->channels_kset;
ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
"%u", relid);
- if (ret)
+ if (ret) {
+ kobject_put(kobj);
return ret;
+ }

ret = sysfs_create_group(kobj, &vmbus_chan_group);

@@ -2038,6 +2040,7 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
* The calling functions' error handling paths will cleanup the
* empty channel directory.
*/
+ kobject_put(kobj);
dev_err(device, "Unable to set up channel sysfs files\n");
return ret;
}
--
2.25.1

2022-02-08 11:25:23

by Juan Vazquez

[permalink] [raw]
Subject: Re: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

On Fri, Feb 04, 2022 at 01:30:08AM +0800, Miaoqian Lin wrote:
> kobject_init_and_add() takes reference even when it fails.
> According to the doc of kobject_init_and_add():
>
> If this function returns an error, kobject_put() must be called to
> properly clean up the memory associated with the object.
>
> Fix memory leak by calling kobject_put().
>
> Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> Changes in v2:
> - Add cleanup when sysfs_create_group() fails
>
> kobject_uevent() is used for notifying userspace by sending an uevent,
> I don't think we need to do error handling for it.

Thanks for the patch. It looks good to me.

Reviewed-by: Juan Vazquez <[email protected]>

> ---
> drivers/hv/vmbus_drv.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 17bf55fe3169..34a4fd21bdf5 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
> kobj->kset = dev->channels_kset;
> ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
> "%u", relid);
> - if (ret)
> + if (ret) {
> + kobject_put(kobj);
> return ret;
> + }
>
> ret = sysfs_create_group(kobj, &vmbus_chan_group);
>
> @@ -2038,6 +2040,7 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
> * The calling functions' error handling paths will cleanup the
> * empty channel directory.
> */
> + kobject_put(kobj);
> dev_err(device, "Unable to set up channel sysfs files\n");
> return ret;
> }
> --
> 2.25.1

2022-02-08 11:29:39

by Wei Liu

[permalink] [raw]
Subject: Re: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

On Sun, Feb 06, 2022 at 06:55:56AM -0800, Juan Vazquez wrote:
> On Fri, Feb 04, 2022 at 01:30:08AM +0800, Miaoqian Lin wrote:
> > kobject_init_and_add() takes reference even when it fails.
> > According to the doc of kobject_init_and_add():
> >
> > If this function returns an error, kobject_put() must be called to
> > properly clean up the memory associated with the object.
> >
> > Fix memory leak by calling kobject_put().
> >
> > Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
> > Signed-off-by: Miaoqian Lin <[email protected]>
> > ---
> > Changes in v2:
> > - Add cleanup when sysfs_create_group() fails
> >
> > kobject_uevent() is used for notifying userspace by sending an uevent,
> > I don't think we need to do error handling for it.
>
> Thanks for the patch. It looks good to me.
>
> Reviewed-by: Juan Vazquez <[email protected]>

Applied to hyperv-fixes. Thanks.