Re: [alsa-devel] [PATCH] ASoC: intel: Fix crash at suspend/resume after failed codec registration

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 3/22/19 6:39 PM, Guenter Roeck wrote:
> If codec registration fails after the ASoC Intel SST driver has been probed,
> the kernel will Oops and crash at suspend/resume.
> 
> general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
> CPU: 1 PID: 2811 Comm: cat Tainted: G        W         4.19.30 #15
> Hardware name: GOOGLE Clapper, BIOS Google_Clapper.5216.199.7 08/22/2014
> RIP: 0010:snd_soc_suspend+0x5a/0xd21
> Code: 03 80 3c 10 00 49 89 d7 74 0b 48 89 df e8 71 72 c4 fe 4c 89
> fa 48 8b 03 48 89 45 d0 48 8d 98 a0 01 00 00 48 89 d8 48 c1 e8 03
> <8a> 04 10 84 c0 0f 85 85 0c 00 00 80 3b 00 0f 84 6b 0c 00 00 48 8b
> RSP: 0018:ffff888035407750 EFLAGS: 00010202
> RAX: 0000000000000034 RBX: 00000000000001a0 RCX: 0000000000000000
> RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88805c417098
> RBP: ffff8880354077b0 R08: dffffc0000000000 R09: ffffed100b975718
> R10: 0000000000000001 R11: ffffffff949ea4a3 R12: 1ffff1100b975746
> R13: dffffc0000000000 R14: ffff88805cba4588 R15: dffffc0000000000
> FS:  0000794a78e91b80(0000) GS:ffff888068d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007bd5283ccf58 CR3: 000000004b7aa000 CR4: 00000000001006e0
> Call Trace:
> ? dpm_complete+0x67b/0x67b
> ? i915_gem_suspend+0x14d/0x1ad
> sst_soc_prepare+0x91/0x1dd
> ? sst_be_hw_params+0x7e/0x7e
> dpm_prepare+0x39a/0x88b
> dpm_suspend_start+0x13/0x9d
> suspend_devices_and_enter+0x18f/0xbd7
> ? arch_suspend_enable_irqs+0x11/0x11
> ? printk+0xd9/0x12d
> ? lock_release+0x95f/0x95f
> ? log_buf_vmcoreinfo_setup+0x131/0x131
> ? rcu_read_lock_sched_held+0x140/0x22a
> ? __bpf_trace_rcu_utilization+0xa/0xa
> ? __pm_pr_dbg+0x186/0x190
> ? pm_notifier_call_chain+0x39/0x39
> ? suspend_test+0x9d/0x9d
> pm_suspend+0x2f4/0x728
> ? trace_suspend_resume+0x3da/0x3da
> ? lock_release+0x95f/0x95f
> ? kernfs_fop_write+0x19f/0x32d
> state_store+0xd8/0x147
> ? sysfs_kf_read+0x155/0x155
> kernfs_fop_write+0x23e/0x32d
> __vfs_write+0x108/0x608
> ? vfs_read+0x2e9/0x2e9
> ? rcu_read_lock_sched_held+0x140/0x22a
> ? __bpf_trace_rcu_utilization+0xa/0xa
> ? debug_smp_processor_id+0x10/0x10
> ? selinux_file_permission+0x1c5/0x3c8
> ? rcu_sync_lockdep_assert+0x6a/0xad
> ? __sb_start_write+0x129/0x2ac
> vfs_write+0x1aa/0x434
> ksys_write+0xfe/0x1be
> ? __ia32_sys_read+0x82/0x82
> do_syscall_64+0xcd/0x120
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> In the observed situation, the problem is seen because the codec driver
> failed to probe due to a hardware problem.
> 
> max98090 i2c-193C9890:00: Failed to read device revision: -1
> max98090 i2c-193C9890:00: ASoC: failed to probe component -1
> cht-bsw-max98090 cht-bsw-max98090: ASoC: failed to instantiate card -1
> cht-bsw-max98090 cht-bsw-max98090: snd_soc_register_card failed -1
> cht-bsw-max98090: probe of cht-bsw-max98090 failed with error -1
> 
> The problem is similar to the problem solved with commit 2fc995a87f2e
> ("ASoC: intel: Fix crash at suspend/resume without card registration"),
> but codec registration fails at a later point. At that time, the pointer
> checked with the above mentioned commit is already set, but it is not
> cleared if the device is subsequently removed. Adding a remove function
> to clear the pointer fixes the problem.

Makes sense

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

I'd like to highlight that there is a fundamental flaw in the way the 
machine drivers are handled. Since we don't have a hook for the machine 
driver in the BIOS, the DSP driver creates a platform_device which will 
instantiate the machine driver. When errors happen in the machine driver 
probe, they are suppressed due to a 'feature' of the device model, so 
you can end-up with a broken configuration that is still reported as a 
successful strobe.

> 
> Cc: stable@vger.kernel.org
> Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> Cc: Curtis Malainey <cujomalainey@chromium.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>   sound/soc/intel/atom/sst-mfld-platform-pcm.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> index 08cea5b5cda9..0e8b1c5eec88 100644
> --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> @@ -706,9 +706,17 @@ static int sst_soc_probe(struct snd_soc_component *component)
>   	return sst_dsp_init_v2_dpcm(component);
>   }
>   
> +static void sst_soc_remove(struct snd_soc_component *component)
> +{
> +	struct sst_data *drv = dev_get_drvdata(component->dev);
> +
> +	drv->soc_card = NULL;
> +}
> +
>   static const struct snd_soc_component_driver sst_soc_platform_drv  = {
>   	.name		= DRV_NAME,
>   	.probe		= sst_soc_probe,
> +	.remove		= sst_soc_remove,
>   	.ops		= &sst_platform_ops,
>   	.compr_ops	= &sst_platform_compr_ops,
>   	.pcm_new	= sst_pcm_new,
>