[alsa-devel] [PATCH] ASoC: core: delete component->card_list in soc_remove_component only

Wed Sep 18 04:47:28 CEST 2019

> -----Original Message-----
> From: Kuninori Morimoto [mailto:kuninori.morimoto.gx at renesas.com]
> Sent: Wednesday, September 18, 2019 8:52 AM
> To: Bard liao <yung-chuan.liao at linux.intel.com>
> Cc: broonie at kernel.org; tiwai at suse.de; alsa-devel at alsa-project.org; pierre-
> louis.bossart at linux.intel.com; Liao, Bard <bard.liao at intel.com>
> Subject: Re: [PATCH] ASoC: core: delete component->card_list in
> soc_remove_component only
> 
> 
> Hi Bard
> 
> Thank you for your patch
> 
> > From: Bard Liao <yung-chuan.liao at linux.intel.com>
> >
> > We add component->card_list in the end of soc_probe_component(). In
> > other words, component->card_list will not be added if there is an
> > error in the soc_probe_component() function. So we can't delete
> > component->card_list in the error handling of soc_probe_component().
> >
> > Fixes: 22d1423187e5 ("ASoC: soc-core: add soc_cleanup_component()")
> > Signed-off-by: Bard Liao <yung-chuan.liao at linux.intel.com>
> > ---
> 
> Hmm... what happen if you get error at soc_probe_component() ?
> What does your "can't delete component->card_list" mean ?
> Kernel Oops or warning ?

That is Kernel Oops, see the dmesg below.
[   84.180608] rt711 sdw:0:25d:711:0:1: ASoC: failed to probe component -517
[   84.180653] sdw_rt711_rt1308_rt715 sdw_rt711_rt1308_rt715: ASoC: failed to instantiate card -517
[   84.180701] sdw_rt711_rt1308_rt715 sdw_rt711_rt1308_rt715: snd_soc_register_card failed -517
...
[   94.419962] rt711 sdw:0:25d:711:0:1: ASoC: failed to probe component -517
[   94.419983] general protection fault: 0000 [#1] SMP PTI
[   94.419986] CPU: 6 PID: 119 Comm: kworker/6:1 Not tainted 5.3.0-rc7+ #821
[   94.419988] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3042.A02.1901222005 01/22/2019
[   94.419994] Workqueue: events deferred_probe_work_func
[   94.420012] RIP: 0010:soc_cleanup_component+0x1c/0x70 [snd_soc_core]
[   94.420015] Code: c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 53 31 d2 48 89 fb 31 f6 e8 03 bc 00 00 48 8b 43 58 48 8b 53 50 48 8d bb c0 00 00 00 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 43 50 48
[   94.420017] RSP: 0000:ffffa40340317c38 EFLAGS: 00010246
[   94.420019] RAX: dead000000000122 RBX: ffff8fe22576ac28 RCX: 0000000000000006
[   94.420023] RDX: dead000000000100 RSI: 0000000000000000 RDI: ffff8fe22576ace8
[   94.420024] RBP: ffffffffc07430c0 R08: 0000000000000586 R09: 000000000000004c
[   94.420026] R10: ffffa40340317a68 R11: ffffa403403179a0 R12: ffff8fe22576ac20
[   94.420027] R13: ffff8fe22576ace8 R14: ffff8fe22576ac90 R15: 0000000000000000
[   94.420028] FS:  0000000000000000(0000) GS:ffff8fe227f80000(0000) knlGS:0000000000000000
[   94.420030] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   94.420034] CR2: 00007ffdf5555c40 CR3: 000000028cd5c002 CR4: 0000000000760ee0
[   94.420036] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   94.420037] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   94.420038] PKRU: 55555554
[   94.420039] Call Trace:
[   94.420050]  soc_probe_component+0x218/0x370 [snd_soc_core]
[   94.420059]  snd_soc_instantiate_card+0x4da/0xd10 [snd_soc_core]
[   94.420064]  ? devm_snd_soc_register_card+0x2e/0x80 [snd_soc_core]
[   94.420071]  snd_soc_register_card+0x169/0x190 [snd_soc_core]
[   94.420076]  devm_snd_soc_register_card+0x3e/0x80 [snd_soc_core]
[   94.420082]  mc_probe+0x152/0x1ac [snd_soc_sdw_rt711_rt1308_rt715]
[   94.420087]  ? acpi_dev_pm_attach+0x1b/0xa0
[   94.420090]  platform_drv_probe+0x32/0x90
[   94.420095]  really_probe+0xea/0x3d0
[   94.420097]  ? driver_allows_async_probing+0x50/0x50
[   94.420100]  driver_probe_device+0x10b/0x120
[   94.420102]  ? driver_allows_async_probing+0x50/0x50
[   94.420107]  bus_for_each_drv+0x61/0xa0
[   94.420110]  __device_attach+0xcf/0x150
[   94.420113]  bus_probe_device+0x82/0x90
[   94.420115]  deferred_probe_work_func+0x6f/0xc0
[   94.420121]  process_one_work+0x1e3/0x3d0
[   94.420124]  worker_thread+0x28/0x3c0
[   94.420126]  ? cancel_delayed_work+0x80/0x80
[   94.420128]  kthread+0x10e/0x130
[   94.420132]  ? kthread_park+0xa0/0xa0
[   94.420135]  ret_from_fork+0x35/0x40
[   94.420138] Modules linked in: snd_soc_rt715 snd_soc_rt1308_sdw snd_soc_rt711 regmap_sdw soundwire_intel snd_soc_sdw_rt711_rt1308_rt715 soundwire_cadence snd_soc_hdac_hdmi snd_soc_dmic snd_sof_pci snd_sof_intel_hda_common snd_soc_hdac_hda snd_hda_codec soundwire_intel_init snd_intel_nhlt snd_sof_intel_hda snd_sof_intel_byt snd_soc_acpi_intel_match snd_soc_acpi snd_sof_intel_ipc snd_sof snd_sof_xtensa_dsp snd_hda_ext_core snd_hda_core snd_soc_core snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd soundcore ax88179_178a usbnet x86_pkg_temp_thermal intel_powerclamp intel_lpss_pci mei_me intel_lpss mfd_core mei efivarfs i915 i2c_algo_bit drm_kms_helper syscopyarea xhci_pci sysfillrect sysimgblt sdhci_pci fb_sys_fops cqhci sdhci xhci_hcd drm
[   94.420169] ---[ end trace 32434ffe9a1d6bab ]---

> 
> I tried to create an error on purpose at soc_probe_component(), but, there was
> no kernel oops, no warning, etc.
> It just can't create sound card. It is very normal for me.
> Or, which kernel are you using ?

Somehow I can only see the second attempt of component probe when it return
-517 (EPROBE_DEFER) in the first attempt by using below kernel.
https://github.com/plbossart/sound/commits/fix/soundwire-split-lookup-init

To me, the easiest way to see the issue is force return - EPROBE_DEFER on
codec driver's probe function and call list_del(&component->card_list);
before calling soc_cleanup_component(component);
So list_del() will be called twice and you will see the issue.

> 
> Thank you for your help !!
> Best regards
> ---
> Kuninori Morimoto