Hi, Adam,
-----Original Message----- From: Adam Thomson Adam.Thomson.Opensource@diasemi.com Sent: Thursday, July 30, 2020 10:54 AM To: Zhi, Yong yong.zhi@intel.com; alsa-devel@alsa-project.org; broonie@kernel.org Cc: pierre-louis.bossart@linux.intel.com; Adam Thomson Adam.Thomson.Opensource@diasemi.com Subject: RE: [PATCH] ASoC: da7219: Fix general protection fault in da7219_register_dai_clks
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@intel.com
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
When the card was uninstalled with modprobe -r, the da7219 codec was not removed, only component da7219_remove() is invoked, do you suggest the component driver probe and remove has to happen with da7219_i2_driver probe and remove together? Thanks for the code review.
-- 2.7.4