| Message ID | 6fbfc0b8aa75852c4eed4d05e4c165a493304ced.1519811528.git.arvind.yadav.cs@gmail.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: iucv: Free memory obtained by kzalloc | expand |
On Wed, 28 Feb 2018 15:24:16 +0530 Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > Free memory, if afiucv_iucv_init is not successful and > removing a IUCV driver. > > Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> > --- > net/iucv/af_iucv.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c > index 1e8cc7b..eb0995a 100644 > --- a/net/iucv/af_iucv.c > +++ b/net/iucv/af_iucv.c > @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) > af_iucv_dev->driver = &af_iucv_driver; > err = device_register(af_iucv_dev); > if (err) > - goto out_driver; > + goto out_iucv_dev; > return 0; > > +out_iucv_dev: > + kfree(af_iucv_dev); > out_driver: > driver_unregister(&af_iucv_driver); > out_iucv: > @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) > { > if (pr_iucv) { > device_unregister(af_iucv_dev); > + kfree(af_iucv_dev); > driver_unregister(&af_iucv_driver); > pr_iucv->iucv_unregister(&af_iucv_handler, 0); > symbol_put(iucv_if); No, you must not use kfree() after you called device_register() (even if it was not successful!) -- see the comment for device_register().
On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote: > On Wed, 28 Feb 2018 15:24:16 +0530 > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > >> Free memory, if afiucv_iucv_init is not successful and >> removing a IUCV driver. >> >> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> >> --- >> net/iucv/af_iucv.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c >> index 1e8cc7b..eb0995a 100644 >> --- a/net/iucv/af_iucv.c >> +++ b/net/iucv/af_iucv.c >> @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) >> af_iucv_dev->driver = &af_iucv_driver; >> err = device_register(af_iucv_dev); >> if (err) >> - goto out_driver; >> + goto out_iucv_dev; >> return 0; >> >> +out_iucv_dev: >> + kfree(af_iucv_dev); >> out_driver: >> driver_unregister(&af_iucv_driver); >> out_iucv: >> @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) >> { >> if (pr_iucv) { >> device_unregister(af_iucv_dev); >> + kfree(af_iucv_dev); >> driver_unregister(&af_iucv_driver); >> pr_iucv->iucv_unregister(&af_iucv_handler, 0); >> symbol_put(iucv_if); > No, you must not use kfree() after you called device_register() (even > if it was not successful!) -- see the comment for device_register(). Yes, Your are right. First we need to call put_device() then kfree(). I will send updated patch. ~arvind
On Wed, 28 Feb 2018 17:14:55 +0530 Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote: > > On Wed, 28 Feb 2018 15:24:16 +0530 > > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > > > >> Free memory, if afiucv_iucv_init is not successful and > >> removing a IUCV driver. > >> > >> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> > >> --- > >> net/iucv/af_iucv.c | 5 ++++- > >> 1 file changed, 4 insertions(+), 1 deletion(-) > >> > >> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c > >> index 1e8cc7b..eb0995a 100644 > >> --- a/net/iucv/af_iucv.c > >> +++ b/net/iucv/af_iucv.c > >> @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) > >> af_iucv_dev->driver = &af_iucv_driver; > >> err = device_register(af_iucv_dev); > >> if (err) > >> - goto out_driver; > >> + goto out_iucv_dev; > >> return 0; > >> > >> +out_iucv_dev: > >> + kfree(af_iucv_dev); > >> out_driver: > >> driver_unregister(&af_iucv_driver); > >> out_iucv: > >> @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) > >> { > >> if (pr_iucv) { > >> device_unregister(af_iucv_dev); > >> + kfree(af_iucv_dev); > >> driver_unregister(&af_iucv_driver); > >> pr_iucv->iucv_unregister(&af_iucv_handler, 0); > >> symbol_put(iucv_if); > > No, you must not use kfree() after you called device_register() (even > > if it was not successful!) -- see the comment for device_register(). > Yes, Your are right. First we need to call put_device() then kfree(). > I will send updated patch. No, that's not correct, either. device_register() will give up any reference it obtained, and the caller did not obtain any additional reference, so a put_device() would be wrong. A kfree() on a refcounted structure is wrong as well.
On Wednesday 28 February 2018 05:26 PM, Cornelia Huck wrote: > On Wed, 28 Feb 2018 17:14:55 +0530 > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > >> On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote: >>> On Wed, 28 Feb 2018 15:24:16 +0530 >>> Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: >>> >>>> Free memory, if afiucv_iucv_init is not successful and >>>> removing a IUCV driver. >>>> >>>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> >>>> --- >>>> net/iucv/af_iucv.c | 5 ++++- >>>> 1 file changed, 4 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c >>>> index 1e8cc7b..eb0995a 100644 >>>> --- a/net/iucv/af_iucv.c >>>> +++ b/net/iucv/af_iucv.c >>>> @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) >>>> af_iucv_dev->driver = &af_iucv_driver; >>>> err = device_register(af_iucv_dev); >>>> if (err) >>>> - goto out_driver; >>>> + goto out_iucv_dev; >>>> return 0; >>>> >>>> +out_iucv_dev: >>>> + kfree(af_iucv_dev); >>>> out_driver: >>>> driver_unregister(&af_iucv_driver); >>>> out_iucv: >>>> @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) >>>> { >>>> if (pr_iucv) { >>>> device_unregister(af_iucv_dev); >>>> + kfree(af_iucv_dev); >>>> driver_unregister(&af_iucv_driver); >>>> pr_iucv->iucv_unregister(&af_iucv_handler, 0); >>>> symbol_put(iucv_if); >>> No, you must not use kfree() after you called device_register() (even >>> if it was not successful!) -- see the comment for device_register(). >> Yes, Your are right. First we need to call put_device() then kfree(). >> I will send updated patch. > No, that's not correct, either. device_register() will give up any > reference it obtained, and the caller did not obtain any additional > reference, so a put_device() would be wrong. A kfree() on a refcounted > structure is wrong as well. If you will see the comment for device_register() (drivers/base/core.c) there is mentioned that 'NOTE: _Never_ directly free @dev after calling this function, even if it returned an error! Always use put_device() to give up the reference initialized in this function instead.' But as per you comment. we should not use. Thanks,
Hi, > On Wednesday 28 February 2018 05:26 PM, Cornelia Huck wrote: > > On Wed, 28 Feb 2018 17:14:55 +0530 > > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > > > >> On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote: > >>> On Wed, 28 Feb 2018 15:24:16 +0530 > >>> Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > >>> > >>>> Free memory, if afiucv_iucv_init is not successful and > >>>> removing a IUCV driver. > >>>> > >>>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> > >>>> --- > >>>> net/iucv/af_iucv.c | 5 ++++- > >>>> 1 file changed, 4 insertions(+), 1 deletion(-) > >>>> > >>>> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c > >>>> index 1e8cc7b..eb0995a 100644 > >>>> --- a/net/iucv/af_iucv.c > >>>> +++ b/net/iucv/af_iucv.c > >>>> @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) > >>>> af_iucv_dev->driver = &af_iucv_driver; > >>>> err = device_register(af_iucv_dev); > >>>> if (err) > >>>> - goto out_driver; > >>>> + goto out_iucv_dev; > >>>> return 0; > >>>> > >>>> +out_iucv_dev: > >>>> + kfree(af_iucv_dev); > >>>> out_driver: > >>>> driver_unregister(&af_iucv_driver); > >>>> out_iucv: > >>>> @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) > >>>> { > >>>> if (pr_iucv) { > >>>> device_unregister(af_iucv_dev); > >>>> + kfree(af_iucv_dev); > >>>> driver_unregister(&af_iucv_driver); > >>>> pr_iucv->iucv_unregister(&af_iucv_handler, 0); > >>>> symbol_put(iucv_if); > >>> No, you must not use kfree() after you called device_register() (even > >>> if it was not successful!) -- see the comment for device_register(). > >> Yes, Your are right. First we need to call put_device() then kfree(). > >> I will send updated patch. > > No, that's not correct, either. device_register() will give up any > > reference it obtained, and the caller did not obtain any additional > > reference, so a put_device() would be wrong. A kfree() on a refcounted > > structure is wrong as well. > If you will see the comment for device_register() (drivers/base/core.c) > there is mentioned that > 'NOTE: _Never_ directly free @dev after calling this function, even > if it returned an error! Always use put_device() to give up the > reference initialized in this function instead.' > But as per you comment. we should not use. > Thanks, > In case that device_register() fails simply call device_put(). This will decrement the last reference and then free the memory. Regards, Lino
On Wed, 28 Feb 2018 17:39:53 +0530 Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > On Wednesday 28 February 2018 05:26 PM, Cornelia Huck wrote: > > On Wed, 28 Feb 2018 17:14:55 +0530 > > Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > > > >> On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote: > >>> On Wed, 28 Feb 2018 15:24:16 +0530 > >>> Arvind Yadav <arvind.yadav.cs@gmail.com> wrote: > >>> > >>>> Free memory, if afiucv_iucv_init is not successful and > >>>> removing a IUCV driver. > >>>> > >>>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> > >>>> --- > >>>> net/iucv/af_iucv.c | 5 ++++- > >>>> 1 file changed, 4 insertions(+), 1 deletion(-) > >>>> > >>>> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c > >>>> index 1e8cc7b..eb0995a 100644 > >>>> --- a/net/iucv/af_iucv.c > >>>> +++ b/net/iucv/af_iucv.c > >>>> @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) > >>>> af_iucv_dev->driver = &af_iucv_driver; > >>>> err = device_register(af_iucv_dev); > >>>> if (err) > >>>> - goto out_driver; > >>>> + goto out_iucv_dev; > >>>> return 0; > >>>> > >>>> +out_iucv_dev: > >>>> + kfree(af_iucv_dev); > >>>> out_driver: > >>>> driver_unregister(&af_iucv_driver); > >>>> out_iucv: > >>>> @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) > >>>> { > >>>> if (pr_iucv) { > >>>> device_unregister(af_iucv_dev); > >>>> + kfree(af_iucv_dev); > >>>> driver_unregister(&af_iucv_driver); > >>>> pr_iucv->iucv_unregister(&af_iucv_handler, 0); > >>>> symbol_put(iucv_if); > >>> No, you must not use kfree() after you called device_register() (even > >>> if it was not successful!) -- see the comment for device_register(). > >> Yes, Your are right. First we need to call put_device() then kfree(). > >> I will send updated patch. > > No, that's not correct, either. device_register() will give up any > > reference it obtained, and the caller did not obtain any additional > > reference, so a put_device() would be wrong. A kfree() on a refcounted > > structure is wrong as well. > If you will see the comment for device_register() (drivers/base/core.c) > there is mentioned that > 'NOTE: _Never_ directly free @dev after calling this function, even > if it returned an error! Always use put_device() to give up the > reference initialized in this function instead.' > But as per you comment. we should not use. You don't need to do a put_device() after your device_unregister(), that's all managed by the driver core.
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 1e8cc7b..eb0995a 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void) af_iucv_dev->driver = &af_iucv_driver; err = device_register(af_iucv_dev); if (err) - goto out_driver; + goto out_iucv_dev; return 0; +out_iucv_dev: + kfree(af_iucv_dev); out_driver: driver_unregister(&af_iucv_driver); out_iucv: @@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void) { if (pr_iucv) { device_unregister(af_iucv_dev); + kfree(af_iucv_dev); driver_unregister(&af_iucv_driver); pr_iucv->iucv_unregister(&af_iucv_handler, 0); symbol_put(iucv_if);
Free memory, if afiucv_iucv_init is not successful and removing a IUCV driver. Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> --- net/iucv/af_iucv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)