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* [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
@ 2021-11-01  9:55 Dongliang Mu
  2021-11-01 18:32 ` Dan Carpenter
  0 siblings, 1 reply; 6+ messages in thread
From: Dongliang Mu @ 2021-11-01  9:55 UTC (permalink / raw)
  To: Mauro Carvalho Chehab
  Cc: Dongliang Mu, Pavel Skripkin, syzbot, linux-media, linux-kernel

In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
to deallocate the media_dev allocated in the em28xx_media_device_init.

Fix this by adding em28xx_unregister_media_device to free media_dev.

BTW, this patch is tested in my local syzkaller instance, and it can
prevent the memory leak from occurring again.

CC: Pavel Skripkin <paskripkin@gmail.com>
Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
---
 drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index c1e0dccb7408..fca68939ca50 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
 
 	if (dev->is_audio_only) {
 		retval = em28xx_audio_setup(dev);
-		if (retval)
-			return -ENODEV;
+		if (retval) {
+			retval = -ENODEV;
+			goto err_deinit_media;
+		}
 		em28xx_init_extension(dev);
 
 		return 0;
@@ -3645,7 +3647,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
 		dev_err(&dev->intf->dev,
 			"%s: em28xx_i2c_register bus 0 - error [%d]!\n",
 		       __func__, retval);
-		return retval;
+		goto err_deinit_media;
 	}
 
 	/* register i2c bus 1 */
@@ -3661,9 +3663,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
 				"%s: em28xx_i2c_register bus 1 - error [%d]!\n",
 				__func__, retval);
 
-			em28xx_i2c_unregister(dev, 0);
-
-			return retval;
+			goto err_unreg_i2c;
 		}
 	}
 
@@ -3671,6 +3671,13 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
 	em28xx_card_setup(dev);
 
 	return 0;
+
+
+err_unreg_i2c:
+	em28xx_i2c_unregister(dev, 0);
+err_deinit_media:
+	em28xx_unregister_media_device(dev);
+	return retval;
 }
 
 static int em28xx_duplicate_dev(struct em28xx *dev)
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
  2021-11-01  9:55 [PATCH] media: em28xx: fix memory leak in em28xx_init_dev Dongliang Mu
@ 2021-11-01 18:32 ` Dan Carpenter
  2021-11-01 19:28   ` Pavel Skripkin
  0 siblings, 1 reply; 6+ messages in thread
From: Dan Carpenter @ 2021-11-01 18:32 UTC (permalink / raw)
  To: Dongliang Mu
  Cc: Mauro Carvalho Chehab, Pavel Skripkin, syzbot, linux-media, linux-kernel

On Mon, Nov 01, 2021 at 05:55:39PM +0800, Dongliang Mu wrote:
> In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
> to deallocate the media_dev allocated in the em28xx_media_device_init.
> 
> Fix this by adding em28xx_unregister_media_device to free media_dev.
> 
> BTW, this patch is tested in my local syzkaller instance, and it can
> prevent the memory leak from occurring again.
> 
> CC: Pavel Skripkin <paskripkin@gmail.com>
> Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>

Is this really a syzbot warning?  If so it should be in the format:

Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com

Syzbot is different from syzkaller.  Syzkaller is the fuzzer and syzbot
is the program which reports syzkaller bugs.

> ---
>  drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> index c1e0dccb7408..fca68939ca50 100644
> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> @@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
>  

There is no check to see if the em28xx_media_device_init() fails.  I
don't love that we call unregister() to undo the init() but it seems
like it should work...

>  	if (dev->is_audio_only) {
>  		retval = em28xx_audio_setup(dev);
> -		if (retval)
> -			return -ENODEV;
> +		if (retval) {
> +			retval = -ENODEV;

This was in the original code, but probably we should preserve the
error code.

> +			goto err_deinit_media;
> +		}

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
  2021-11-01 18:32 ` Dan Carpenter
@ 2021-11-01 19:28   ` Pavel Skripkin
  2021-11-02  6:31     ` Dongliang Mu
  0 siblings, 1 reply; 6+ messages in thread
From: Pavel Skripkin @ 2021-11-01 19:28 UTC (permalink / raw)
  To: Dan Carpenter, Dongliang Mu
  Cc: Mauro Carvalho Chehab, syzbot, linux-media, linux-kernel

On 11/1/21 21:32, Dan Carpenter wrote:
> On Mon, Nov 01, 2021 at 05:55:39PM +0800, Dongliang Mu wrote:
>> In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
>> to deallocate the media_dev allocated in the em28xx_media_device_init.
>> 
>> Fix this by adding em28xx_unregister_media_device to free media_dev.
>> 
>> BTW, this patch is tested in my local syzkaller instance, and it can
>> prevent the memory leak from occurring again.
>> 
>> CC: Pavel Skripkin <paskripkin@gmail.com>
>> Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
>> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
>> Reported-by: syzbot <syzkaller@googlegroups.com>
> 
> Is this really a syzbot warning?  If so it should be in the format:
> 
> Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
> 
> Syzbot is different from syzkaller.  Syzkaller is the fuzzer and syzbot
> is the program which reports syzkaller bugs.
> 

Bug report is from his local instance. He just wants to give credit to 
syzbot for finding it

>> ---
>>  drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
>>  1 file changed, 13 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
>> index c1e0dccb7408..fca68939ca50 100644
>> --- a/drivers/media/usb/em28xx/em28xx-cards.c
>> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
>> @@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
>>  
> 
> There is no check to see if the em28xx_media_device_init() fails.  I

I guess, it should work, since there a lot of checks to see if this 
pointer is valid, i.e driver can work even without this pointer, AFAIK

> don't love that we call unregister() to undo the init() but it seems
> like it should work...

Same here, but it is out of scope of this patch :)



With regards,
Pavel Skripkin

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
  2021-11-01 19:28   ` Pavel Skripkin
@ 2021-11-02  6:31     ` Dongliang Mu
  2021-11-02 13:50       ` Dan Carpenter
  0 siblings, 1 reply; 6+ messages in thread
From: Dongliang Mu @ 2021-11-02  6:31 UTC (permalink / raw)
  To: Pavel Skripkin
  Cc: Dan Carpenter, Mauro Carvalho Chehab, syzbot, linux-media, linux-kernel

On Tue, Nov 2, 2021 at 3:28 AM Pavel Skripkin <paskripkin@gmail.com> wrote:
>
> On 11/1/21 21:32, Dan Carpenter wrote:
> > On Mon, Nov 01, 2021 at 05:55:39PM +0800, Dongliang Mu wrote:
> >> In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
> >> to deallocate the media_dev allocated in the em28xx_media_device_init.
> >>
> >> Fix this by adding em28xx_unregister_media_device to free media_dev.
> >>
> >> BTW, this patch is tested in my local syzkaller instance, and it can
> >> prevent the memory leak from occurring again.
> >>
> >> CC: Pavel Skripkin <paskripkin@gmail.com>
> >> Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
> >> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> >> Reported-by: syzbot <syzkaller@googlegroups.com>
> >
> > Is this really a syzbot warning?  If so it should be in the format:
> >
> > Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
> >
> > Syzbot is different from syzkaller.  Syzkaller is the fuzzer and syzbot
> > is the program which reports syzkaller bugs.
> >
>
> Bug report is from his local instance. He just wants to give credit to
> syzbot for finding it

Hi Dan,

just as explained by Pavel, I leveraged the local syzkaller instance
to find this bug.

I can modify it to "Reported-by: syzkaller
<syzkaller@googlegroups.com>", this one looks better.

>
> >> ---
> >>  drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
> >>  1 file changed, 13 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> >> index c1e0dccb7408..fca68939ca50 100644
> >> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> >> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> >> @@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
> >>
> >
> > There is no check to see if the em28xx_media_device_init() fails.  I
>
> I guess, it should work, since there a lot of checks to see if this
> pointer is valid, i.e driver can work even without this pointer, AFAIK
>
> > don't love that we call unregister() to undo the init() but it seems
> > like it should work...
>
> Same here, but it is out of scope of this patch :)

From the implementation, em28xx_media_device_init and
em28xx_unregister_media_device should not be a pair of functions
(do/undo).

Maybe I can write em28xx_free_media_device to be paired with
em28xx_media_device_init, like below. And then only call it from the
error handling context.

static void em28xx_free_media_device(struct em28xx *dev)
{
#ifdef CONFIG_MEDIA_CONTROLLER
                kfree(dev->media_dev);
                dev->media_dev = NULL;
#endif
}

>
>
>
> With regards,
> Pavel Skripkin

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
  2021-11-02  6:31     ` Dongliang Mu
@ 2021-11-02 13:50       ` Dan Carpenter
  2021-11-08  1:06         ` Dongliang Mu
  0 siblings, 1 reply; 6+ messages in thread
From: Dan Carpenter @ 2021-11-02 13:50 UTC (permalink / raw)
  To: Dongliang Mu
  Cc: Pavel Skripkin, Mauro Carvalho Chehab, syzbot, linux-media, linux-kernel

On Tue, Nov 02, 2021 at 02:31:26PM +0800, Dongliang Mu wrote:
> On Tue, Nov 2, 2021 at 3:28 AM Pavel Skripkin <paskripkin@gmail.com> wrote:
> >
> > On 11/1/21 21:32, Dan Carpenter wrote:
> > > On Mon, Nov 01, 2021 at 05:55:39PM +0800, Dongliang Mu wrote:
> > >> In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
> > >> to deallocate the media_dev allocated in the em28xx_media_device_init.
> > >>
> > >> Fix this by adding em28xx_unregister_media_device to free media_dev.
> > >>
> > >> BTW, this patch is tested in my local syzkaller instance, and it can
> > >> prevent the memory leak from occurring again.
> > >>
> > >> CC: Pavel Skripkin <paskripkin@gmail.com>
> > >> Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
> > >> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> > >> Reported-by: syzbot <syzkaller@googlegroups.com>
> > >
> > > Is this really a syzbot warning?  If so it should be in the format:
> > >
> > > Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
> > >
> > > Syzbot is different from syzkaller.  Syzkaller is the fuzzer and syzbot
> > > is the program which reports syzkaller bugs.
> > >
> >
> > Bug report is from his local instance. He just wants to give credit to
> > syzbot for finding it
> 
> Hi Dan,
> 
> just as explained by Pavel, I leveraged the local syzkaller instance
> to find this bug.
> 
> I can modify it to "Reported-by: syzkaller
> <syzkaller@googlegroups.com>", this one looks better.
> 

No need for a Reported-by at all, but if you want to credit syzkaller
that's an okay format.

> >
> > >> ---
> > >>  drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
> > >>  1 file changed, 13 insertions(+), 6 deletions(-)
> > >>
> > >> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> > >> index c1e0dccb7408..fca68939ca50 100644
> > >> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> > >> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> > >> @@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
> > >>
> > >
> > > There is no check to see if the em28xx_media_device_init() fails.  I
> >
> > I guess, it should work, since there a lot of checks to see if this
> > pointer is valid, i.e driver can work even without this pointer, AFAIK
> >
> > > don't love that we call unregister() to undo the init() but it seems
> > > like it should work...
> >
> > Same here, but it is out of scope of this patch :)
> 
> >From the implementation, em28xx_media_device_init and
> em28xx_unregister_media_device should not be a pair of functions
> (do/undo).
> 

That's how it is now, but it's not necessarily how it should be.  Anyway,
it's unrelated to you patch.  Just forget I mentioned it.

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] media: em28xx: fix memory leak in em28xx_init_dev
  2021-11-02 13:50       ` Dan Carpenter
@ 2021-11-08  1:06         ` Dongliang Mu
  0 siblings, 0 replies; 6+ messages in thread
From: Dongliang Mu @ 2021-11-08  1:06 UTC (permalink / raw)
  To: Dan Carpenter
  Cc: Pavel Skripkin, Mauro Carvalho Chehab, syzbot, linux-media, linux-kernel

On Tue, Nov 2, 2021 at 9:51 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Tue, Nov 02, 2021 at 02:31:26PM +0800, Dongliang Mu wrote:
> > On Tue, Nov 2, 2021 at 3:28 AM Pavel Skripkin <paskripkin@gmail.com> wrote:
> > >
> > > On 11/1/21 21:32, Dan Carpenter wrote:
> > > > On Mon, Nov 01, 2021 at 05:55:39PM +0800, Dongliang Mu wrote:
> > > >> In the em28xx_init_rev, if em28xx_audio_setup fails, this function fails
> > > >> to deallocate the media_dev allocated in the em28xx_media_device_init.
> > > >>
> > > >> Fix this by adding em28xx_unregister_media_device to free media_dev.
> > > >>
> > > >> BTW, this patch is tested in my local syzkaller instance, and it can
> > > >> prevent the memory leak from occurring again.
> > > >>
> > > >> CC: Pavel Skripkin <paskripkin@gmail.com>
> > > >> Fixes: 37ecc7b1278f ("[media] em28xx: add media controller support")
> > > >> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> > > >> Reported-by: syzbot <syzkaller@googlegroups.com>
> > > >
> > > > Is this really a syzbot warning?  If so it should be in the format:
> > > >
> > > > Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
> > > >
> > > > Syzbot is different from syzkaller.  Syzkaller is the fuzzer and syzbot
> > > > is the program which reports syzkaller bugs.
> > > >
> > >
> > > Bug report is from his local instance. He just wants to give credit to
> > > syzbot for finding it
> >
> > Hi Dan,
> >
> > just as explained by Pavel, I leveraged the local syzkaller instance
> > to find this bug.
> >
> > I can modify it to "Reported-by: syzkaller
> > <syzkaller@googlegroups.com>", this one looks better.
> >
>
> No need for a Reported-by at all, but if you want to credit syzkaller
> that's an okay format.
>

Hi all,

do I need to send a v2 patch with a new Reported-by tag?

> > >
> > > >> ---
> > > >>  drivers/media/usb/em28xx/em28xx-cards.c | 19 +++++++++++++------
> > > >>  1 file changed, 13 insertions(+), 6 deletions(-)
> > > >>
> > > >> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> > > >> index c1e0dccb7408..fca68939ca50 100644
> > > >> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> > > >> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> > > >> @@ -3625,8 +3625,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
> > > >>
> > > >
> > > > There is no check to see if the em28xx_media_device_init() fails.  I
> > >
> > > I guess, it should work, since there a lot of checks to see if this
> > > pointer is valid, i.e driver can work even without this pointer, AFAIK
> > >
> > > > don't love that we call unregister() to undo the init() but it seems
> > > > like it should work...
> > >
> > > Same here, but it is out of scope of this patch :)
> >
> > >From the implementation, em28xx_media_device_init and
> > em28xx_unregister_media_device should not be a pair of functions
> > (do/undo).
> >
>
> That's how it is now, but it's not necessarily how it should be.  Anyway,
> it's unrelated to you patch.  Just forget I mentioned it.
>
> regards,
> dan carpenter
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-11-08  1:06 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-01  9:55 [PATCH] media: em28xx: fix memory leak in em28xx_init_dev Dongliang Mu
2021-11-01 18:32 ` Dan Carpenter
2021-11-01 19:28   ` Pavel Skripkin
2021-11-02  6:31     ` Dongliang Mu
2021-11-02 13:50       ` Dan Carpenter
2021-11-08  1:06         ` Dongliang Mu

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