Re: [PATCH] ASoC: intel: Fix crash at suspend/resume without card registration

[Takashi Iwai <tiwai@suse.de>]

On Fri, 25 Nov 2016 14:58:55 +0100,
Takashi Iwai wrote:
> 
> When ASoC Intel SST Medfield driver is probed but without codec / card
> assigned, it causes an Oops and freezes the kernel at suspend/resume,
> 
>  PM: Suspending system (freeze)
>  Suspending console(s) (use no_console_suspend to debug)
>  BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
>  IP: [<ffffffffc09d9409>] sst_soc_prepare+0x19/0xa0 [snd_soc_sst_mfld_platform]
>  Oops: 0000 [#1] PREEMPT SMP
>  CPU: 0 PID: 1552 Comm: systemd-sleep Tainted: G W 4.9.0-rc6-1.g5f5c2ad-default #1
>  Call Trace:
>   [<ffffffffb45318f9>] dpm_prepare+0x209/0x460
>   [<ffffffffb4531b61>] dpm_suspend_start+0x11/0x60
>   [<ffffffffb40d3cc2>] suspend_devices_and_enter+0xb2/0x710
>   [<ffffffffb40d462e>] pm_suspend+0x30e/0x390
>   [<ffffffffb40d2eba>] state_store+0x8a/0x90
>   [<ffffffffb43c670f>] kobj_attr_store+0xf/0x20
>   [<ffffffffb42b0d97>] sysfs_kf_write+0x37/0x40
>   [<ffffffffb42b02bc>] kernfs_fop_write+0x11c/0x1b0
>   [<ffffffffb422be68>] __vfs_write+0x28/0x140
>   [<ffffffffb43728a8>] ? apparmor_file_permission+0x18/0x20
>   [<ffffffffb433b2ab>] ? security_file_permission+0x3b/0xc0
>   [<ffffffffb422d095>] vfs_write+0xb5/0x1a0
>   [<ffffffffb422e3d6>] SyS_write+0x46/0xa0
>   [<ffffffffb4719fbb>] entry_SYSCALL_64_fastpath+0x1e/0xad
> 
> Add proper NULL checks in the PM code of mdfld driver.
> 
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  sound/soc/intel/atom/sst-mfld-platform-pcm.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> index 25c6d87c818e..76bcb947b31c 100644
> --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> @@ -771,6 +771,9 @@ static int sst_soc_prepare(struct device *dev)
>  	struct sst_data *drv = dev_get_drvdata(dev);
>  	struct snd_soc_pcm_runtime *rtd;
>  
> +	if (!drv->soc_card)
> +		return 0;
> +
>  	/* suspend all pcms first */
>  	snd_soc_suspend(drv->soc_card->dev);
>  	snd_soc_poweroff(drv->soc_card->dev);
> @@ -793,6 +796,9 @@ static void sst_soc_complete(struct device *dev)
>  	struct sst_data *drv = dev_get_drvdata(dev);
>  	struct snd_soc_pcm_runtime *rtd;
>  
> +	if (!drv->soc_card)
> +		return 0;

My bad, this is a void function, the return value should be omitted.
Will respin the patch soon...


Takashi