On 30 July 2020 15:04, Yong Zhi wrote:
> clkdev_drop(cl) does not null the removed cl, if da7219_register_dai_clks()
> entered again after card removal, devm_clk_register() will return -EEXIST,
> the goto err to clkdev_drop() will trigger board reboot.
>
> Test commands:
> modprobe -r snd_sof_pci
> modprobe snd_sof_pci
>
> The oops looks like:
>
> da7219 i2c-DLGS7219:00: Using default DAI clk names: da7219-dai-wclk, da7219-
> dai-bclk
> da7219 i2c-DLGS7219:00: Failed to register da7219-dai-wclk: -17
> general protection fault: 0000 [#1] PREEMPT SMP NOPTI
> RIP: 0010:clkdev_drop+0x20/0x52
> Call Trace:
> da7219_probe+0x52e/0x6dc [snd_soc_da7219]
> soc_probe_component+0x206/0x3a1
> snd_soc_bind_card+0x4ee/0x9a6
> devm_snd_soc_register_card+0x48/0x7b
> audio_probe+0x1f0/0x221 [snd_soc_sof_da7219_max98373]
> platform_drv_probe+0x89/0xa2
> really_probe+0x129/0x30d
> driver_probe_device+0x59/0xec
> ? driver_sysfs_remove+0x55/0x55
> bus_for_each_drv+0xa1/0xdc
> __device_attach+0xc2/0x146
> bus_probe_device+0x32/0x97
> device_add+0x311/0x3b4
> platform_device_add+0x184/0x1eb
>
> Fix by marking (nullifying) the da7219->dai_clks_lookup[i]
> after clkdev_drop().
>
> Signed-off-by: Yong Zhi <yong.zhi@xxxxxxxxx>
> ---
> sound/soc/codecs/da7219.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
> index 153ea30b5a8f..54da7cfbb5f4 100644
> --- a/sound/soc/codecs/da7219.c
> +++ b/sound/soc/codecs/da7219.c
> @@ -2369,8 +2369,10 @@ static void da7219_remove(struct
> snd_soc_component *component)
>
> #ifdef CONFIG_COMMON_CLK
> for (i = DA7219_DAI_NUM_CLKS - 1; i >= 0; --i) {
> - if (da7219->dai_clks_lookup[i])
> + if (da7219->dai_clks_lookup[i]) {
> clkdev_drop(da7219->dai_clks_lookup[i]);
> + da7219->dai_clks_lookup[i] = NULL;
> + }
It seems to me that devm_* functions should have freed up everything when the
codec module was removed. I can only assume the codec isn't being removed in
your test hence devm is never freeing the clock resource and is why you're
getting -EEXIST. Is this the case and is your use-case expected behaviour? It's
not something that has been reported previously so am keen to understand exactly
what's happening here.
> }
> #endif
>
> --
> 2.7.4
