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

[Guenter Roeck <linux@roeck-us.net>]

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.

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,
-- 
2.7.4