From: Julia Lawall <julia.lawall@lip6.fr>
To: "Frank Schäfer" <fschaefer.oss@googlemail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
Mauro Carvalho Chehab <m.chehab@samsung.com>,
linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] [media] em28xx-input: NULL dereference on error
Date: Thu, 25 Sep 2014 17:37:46 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.10.1409251736480.2766@hadrien> (raw)
In-Reply-To: <542421DF.9060000@googlemail.com>
[-- Attachment #1: Type: TEXT/PLAIN, Size: 1562 bytes --]
On Thu, 25 Sep 2014, Frank Schäfer wrote:
> Hi Dan,
>
> Am 25.09.2014 um 13:39 schrieb Dan Carpenter:
> > We call "kfree(ir->i2c_client);" in the error handling and that doesn't
> > work if "ir" is NULL.
> >
> > Fixes: 78e719a5f30b ('[media] em28xx-input: i2c IR decoders: improve i2c_client handling')
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >
> > diff --git a/drivers/media/usb/em28xx/em28xx-input.c b/drivers/media/usb/em28xx/em28xx-input.c
> > index 581f6da..23f8f6a 100644
> > --- a/drivers/media/usb/em28xx/em28xx-input.c
> > +++ b/drivers/media/usb/em28xx/em28xx-input.c
> > @@ -712,8 +712,10 @@ static int em28xx_ir_init(struct em28xx *dev)
> > em28xx_info("Registering input extension\n");
> >
> > ir = kzalloc(sizeof(*ir), GFP_KERNEL);
> > + if (!ir)
> > + return -ENOMEM;
> > rc = rc_allocate_device();
> > - if (!ir || !rc)
> > + if (!rc)
> > goto error;
I have never understood this kind of code. If the kmalloc fails, why not
give up immediately (as in Dan's patch)?
julia
> > /* record handles to ourself */
> I would prefer to fix it where the actual problem is located.
> Can you send an updated version that changes the code to do
>
> ...
> error:
> if (ir)
> kfree(ir->i2c_client);
> ...
>
> This makes the code less prone to future error handling changes.
>
> Thanks !
>
> Regards,
> Frank
>
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>
next prev parent reply other threads:[~2014-09-25 15:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-25 11:39 [patch] [media] em28xx-input: NULL dereference on error Dan Carpenter
2014-09-25 14:08 ` Frank Schäfer
2014-09-25 14:49 ` Dan Carpenter
2014-09-25 17:50 ` Frank Schäfer
2014-09-25 15:37 ` Julia Lawall [this message]
2014-09-25 16:28 ` Mauro Carvalho Chehab
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