Messages in this thread | | | Date | Wed, 16 Aug 2006 22:22:46 +0200 | From | "Jesper Juhl" <> | Subject | Re: [PATCH] ISDN: fix double free bug in isdn_net |
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On 15/08/06, Karsten Keil <kkeil@suse.de> wrote: > On Tue, Aug 15, 2006 at 02:15:03AM -0700, David Miller wrote: > > From: "Jesper Juhl" <jesper.juhl@gmail.com> > > Date: Tue, 15 Aug 2006 11:08:35 +0200 > > > > > Hmm, perhaps I made a mistake and missed a path. Maybe it would be > > > better to fix if by making isdn_writebuf_skb_stub() always set the skb > > > to NULL when it does free it. That would add a few more assignments > > > but should ensure the right result always. > > > What do you say? > > > > Do we know if the ->writebuf_skb() method ever frees the skb? If it > > never does, then yes your suggestion would be one way to handle this. > > > It does if it consumes the skb (then it returns skb->len). > But the skb have not to be freed imediately in this case, it maybe > queued or used until all bytes are written to the physical device. > > If it returns any other value the skb is not freed. > > This logic came from using skb for transparent data too. > Here it was possible, that the hw driver only take some bytes from the > skb (so it returns < skb->len), then the isdn layer should requeue > the skb so no transparent data get lost. > > But this mechanism was never used in drivers, only 3 states: > > The driver accept the packet then it is responsible for the skb > and return skb->len or the driver do not accept it (e.g. buffer full, > conntection is going down), then it return 0 and does not free the > skb. > > If some internal error in the HW driver occur, it should return a > negative value and it also do not free the skb. >
Ok, if I understand you correctly, then there's no actual problem here. right?
-- Jesper Juhl <jesper.juhl@gmail.com> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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