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.