Hi Dmitriy,
On Fri, May 27, 2011 at 3:03 PM, Dmitriy Paliy <dmitriy.paliy@xxxxxxxxx> wrote:
> Hi Luiz,
>
> On Fri, 2011-05-27 at 14:56 +0300, ext Luiz Augusto von Dentz wrote:
>> Hi Dmitry,
>>
>> On Fri, May 27, 2011 at 2:26 PM, Dmitriy Paliy <dmitriy.paliy@xxxxxxxxx> wrote:
>> > Fixed incorrect update of transport->owners GSlist in media_transport_free.
>> > Removal of list entries within 'for' loop leads to invalid read of memory
>> > (l = l->next) and memory leaks.
>> > ---
>> > audio/transport.c | 15 +++++++++++----
>> > 1 files changed, 11 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/audio/transport.c b/audio/transport.c
>> > index aa3308d..4047d80 100644
>> > --- a/audio/transport.c
>> > +++ b/audio/transport.c
>> > @@ -805,14 +805,21 @@ static GDBusSignalTable transport_signals[] = {
>> > { }
>> > };
>> >
>> > +static void media_transport_remove_helper(gpointer data, gpointer user_data)
>> > +{
>> > + struct media_transport *transport = user_data;
>> > + struct media_owner *owner = data;
>> > +
>> > + media_transport_remove(transport, owner);
>> > +}
>> > +
>> > +
>> > static void media_transport_free(void *data)
>> > {
>> > struct media_transport *transport = data;
>> > - GSList *l;
>> > -
>> > - for (l = transport->owners; l; l = l->next)
>> > - media_transport_remove(transport, l->data);
>> >
>> > + g_slist_foreach(transport->owners, media_transport_remove_helper,
>> > + transport);
>> > g_slist_free(transport->owners);
>> >
>> > if (transport->session)
>> > --
>> > 1.7.4.1
>>
>> Usually we should just use while (list) and do the list = list->next
>> before item removal.
>
> This is how it is done in the g_slist_foreach function. Therefore, may
> be it is better to use ready function without exposing implementation
> details of this loop.
Well normally it is more code to do it via g_slist_foreach than on
while loop, it is probably more expensive too since it has to call a
callback for each element and obviously the g_slist_foreach has to
take care of prefetch next element.
--
Luiz Augusto von Dentz
Computer Engineer
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