[alsa-devel] Bug in hdmi codec driver in DPCM

[Rohit Kumar]

Hi,

We are facing crash in hdmi codec driver when we use DPCM based 
dai-links. Crash is happening in hdmi_codec_eld_chmap() while accessing 
chmap_info struct during hdmi_codec_startup(). However, chmap_info 
struct is allocated in hdmi_codec_pcm_new() which is only called in 
non-DPCM based dai-links.

Below is the crash stack:

[61.635493] Unable to handle kernel NULL pointer dereference at virtual 
address 00000018

.....

[61.666696]CM = 0, WnR = 1

[61.669778] user pgtable: 4k pages, 39-bit VAs, pgd = ffffffc0d6633000

[61.676526] [0000000000000018] *pgd=0000000153fc8003, 
*pud=0000000153fc8003, *pmd=0000000000000000

[61.685793] Internal error: Oops: 96000046 [#1] PREEMPT SMP

[61.722955] CPU: 7 PID: 2238 Comm: aplay Not tainted 4.14.72 #21

..

[61.740269] PC is at hdmi_codec_startup+0x124/0x164

[61.745308] LR is at hdmi_codec_startup+0xe4/0x164

..

We would probably need to move the implementation on pcm_new() to some 
other function to make it compatible with DPCM.

Can you please provide suggestions in solving the issue.


Thanks,

Rohit