On Thu, 26 Nov 2015 12:01:23 +0100, Mark Brown wrote: > > On Thu, Nov 26, 2015 at 10:19:51AM +0100, Takashi Iwai wrote: > > Vinod Koul wrote: > > > > So in SKL, we do request firmware of topology binary and topology core uses > > > that for strings here, so the patch 87b5ed8ec freed the topology binary > > > which causes panic while accessing kcontrols. > > > This is strange. If it's about the kctl name string, the panic > > shouldn't happen at accessing the kctl but at instantiating the kctl > > from snd_kcontrol_new that contains the invalid string pointer. > > The kctl object contains the string in itself, and there copies the > > string from the template. > > I guess it's possible that if the control creation happens soon enough > after the memory is freed the data will still be valid. This could be > tested for by hacking things to deliberately trash the memory before we > get to control creation. > > > You really need to identify which path hits the issue exactly how. In > > general, the string passed to template is only for creating the kctl. > > Once when kctl is created, the whole snd_kcontrol_new template and the > > allocated string is no use, so they can be freed. > > That does suggest a fairly simple fix of just holding on to the firmware > for longer assuming that the analysis is correct. Right, that would be the simplest fix. Just assure that the whole f/w image is kept until all objects are instantiated. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
