[alsa-devel] Kernel crash at snd_ctl_find_numid+0x38/0x6c in kernel 4.4

[Rohit Kumar]

Hi,

I am getting NULL pointer dereference occasionally at snd_ctl_find_numid+0x38/0x6c in 4.4 kernel while accessing snd_kcontrol. The issue is reproduced ocassionally. Can anybody provide any pointer in fixing the issue. Below is the stack trace :

  2662.430298:   <2> PC is at snd_ctl_find_numid+0x38/0x6c
  2662.437819:   <2> LR is at snd_ctl_find_id+0x38/0xd8
  2662.662838:   <2> [<ffffff8008c4e35c>] snd_ctl_find_numid+0x38/0x6c
  2662.667513:   <2> [<ffffff8008c4e900>] snd_ctl_find_id+0x38/0xd8
  2662.673415:   <2> [<ffffff8008c4f488>] snd_ctl_elem_info+0x40/0x11c
  2662.678799:   <2> [<ffffff8008c4df5c>] snd_ctl_ioctl_compat+0x3f4/0x740
  2662.684644:   <2> [<ffffff800823477c>] compat_SyS_ioctl+0x124/0xd88


There is no specific usecase when the issue is observed. Sometimes issue occurs during bootup and sometimes during audio usecase.

 Any suggestion will be helpful.


Thanks,

Rohit