On Wed, 10 Feb 2016 08:41:38 +0100, Jerome Marchand wrote: > > ----- Original Message ----- > > From: "Takashi Iwai" <tiwai@xxxxxxx> > > To: "Jerome Marchand" <jmarchan@xxxxxxxxxx> > > Cc: "Jaroslav Kysela" <perex@xxxxxxxx>, alsa-devel@xxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx > > Sent: Tuesday, February 9, 2016 10:56:39 PM > > Subject: Re: Should snd_card_free() check for null pointer? > > > > On Tue, 09 Feb 2016 15:30:16 +0100, > > Jerome Marchand wrote: > > > > > > Hi, > > > > > > Before commit f24640648186b (ALSA: Use standard device refcount for card > > > accounting), snd_card_free() would return -EINVAL on a null pointer. Now > > > it ends up in a null pointer dereference. There is at least one driver > > > that can call snd_card_free() with null argument: saa7134_alsa. It can > > > easily be triggered by just inserting and removing the module (no need > > > to have the hardware). > > > I don't think that is a rule, but it seems that the standard behavior of > > > *_free() functions is to check for null pointer. What do you think? > > > > Well, I have a mixed feeling about this. Allowing NULL sometimes > > makes the code easier. OTOH, caling snd_card_free() with NULL is > > really an unexpected situation, and if a driver does it, most likely > > it does something weird. > > > > So, at this moment, I would fix the caller side. But, it's not a > > final call, just my gut feeling. > > I have no strong opinion either way and I have a patch that fixes saa7134 > driver ready to be sent if that is your preference. Go ahead, let's fix saa7134 side for now. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
