On Tue, 12 Jul 2022 11:42:56 +0200, Cezary Rojewski wrote: > > On 2022-07-11 4:12 PM, Takashi Iwai wrote: > > On Mon, 11 Jul 2022 10:25:17 +0200, > > Cezary Rojewski wrote: > > ... > > >> avs-driver i.e. the bus driver takes responsibility for the codec > >> device only. There is no real probe(), just the device creation and > >> initialization of its fields. The rest is handled by the component > >> driver (sound/soc/hda.c). If this field is cleared and the test is > >> limited to reloading HDAudio codec module alone, we get a > >> panic. Something similar to the stack found below my message. > >> > >> In regard to the other question - are presets freed at all? It seems > >> all of them are part of the static device-driver matching list. If so, > >> the pointer is always valid. > > > > When the codec driver is unbound and the module is unloaded, the whole > > objects and symbols are gone. > > > hda_codec_driver_remove() won't get even called when soc-card is being > unbound so everything is still here. > > >> [ 136.827856] RIP: 0010:hda_codec_probe+0x16c/0x560 [snd_soc_hda_codec] > > >> [ 136.828568] Call Trace: > >> [ 136.828593] <TASK> > >> [ 136.828628] snd_soc_component_probe+0x3a/0x60 [snd_soc_core] > >> [ 136.828981] soc_probe_component+0x276/0x4a0 [snd_soc_core] > >> [ 136.829274] snd_soc_bind_card+0x819/0x13d0 [snd_soc_core] > >> [ 136.829560] ? __kasan_slab_alloc+0x32/0x90 > >> [ 136.829614] snd_soc_register_card+0x24e/0x260 [snd_soc_core] > >> [ 136.829900] devm_snd_soc_register_card+0x48/0x90 [snd_soc_core] > >> [ 136.830204] avs_hdaudio_probe+0x298/0x2c0 [snd_soc_avs_hdaudio] > > >> (...) > > > > Hmm, in the Oops above, at which moment, > > snd_hda_codec_cleanup_for_unbind() is called via which function? > > Is it the unload of HD-audio codec driver during the probe of AVS > > HD-audio? > > > > The preset is assigned to the given HD-audio device object for the > > attached codec driver. Once after the codec driver gets unbound, you > > must not access to this codec driver's methods any longer, hence we > > clear the preset field. > > > > So I wonder how the access to the codec->preset happens after the > > codec unbind. > > > Test scenario: > - enumerate avs-driver stack on machine with HDAudio codec present > - rmmod snd_soc_avs_hdaudio // just the machine board driver > i.e. soc-card driver > - modprobe snd_soc_avs_hdaudio > >>> panic <<< > > snd_hda_codec_cleanup_for_unbind() is called in more places than just > HDAudio codec driver's probe() and remove(). It's also called whenever > HDAudio codec soc-component is being removed. Relevant part of the > stack showing when does the cleanup function get called during rmmod: > > [ 220.549349] snd_hda_codec_cleanup_for_unbind+0x25/0x451 [snd_hda_codec] > [ 220.549536] ? dump_stack_lvl+0x45/0x49 > [ 220.549568] hda_codec_remove.cold+0x14/0x138 [snd_soc_hda_codec] > [ 220.549609] snd_soc_component_remove+0x34/0x40 [snd_soc_core] > [ 220.549942] soc_remove_component+0x113/0x120 [snd_soc_core] > [ 220.550249] soc_cleanup_card_resources+0x1a7/0x4a0 [snd_soc_core] > [ 220.550561] snd_soc_unbind_card+0x9e/0x190 [snd_soc_core] > [ 220.550885] snd_soc_unregister_card+0x28/0x80 [snd_soc_core] > [ 220.551193] devm_card_release+0x1d/0x20 [snd_soc_core] > [ 220.551527] release_nodes+0x73/0x170 > [ 220.551549] ? preempt_count_sub+0x18/0xc0 > [ 220.551576] devres_release_all+0x10a/0x150 > [ 220.551600] ? devres_remove_group+0x260/0x260 > [ 220.551630] device_unbind_cleanup+0x14/0xd0 > [ 220.551656] device_release_driver_internal+0x146/0x1d0 > [ 220.551688] driver_detach+0x81/0xf0 > [ 220.551716] bus_remove_driver+0xae/0x170 > [ 220.551743] driver_unregister+0x4d/0x70 > [ 220.551770] platform_driver_unregister+0x12/0x20 > [ 220.551799] avs_hdaudio_driver_exit+0x10/0x12 [snd_soc_avs_hdaudio] So, IMO, you're scratching a wrong surface. The problem is rather that snd_hda_codec_cleanup_for_unbind() is called even if it's not for unbinding the codec. Takashi
