[alsa-devel] [PATCH v2] ALSA: ASoC: soc-compress.c: fix NULL dereference

[James Hogan]

On 13 January 2015 15:16:10 GMT+00:00, Qais Yousef <qais.yousef at imgtec.com> wrote:
>On 01/13/2015 02:59 PM, Vinod Koul wrote:
>> On Tue, Jan 13, 2015 at 11:18:53AM +0000, Qais Yousef wrote:
>>> In soc_new_compress() when rtd->dai_link->daynmic is set, we create
>the pcm
>> 					   ^^^^^^^^
>> typo
>>> substreams with this call:
>>>
>>>     ret = snd_pcm_new_internal(rtd->card->snd_card, new_name, num,
>>>                                     1, 0, &be_pcm);
>>>
>>> which passes 0 as capture_count leading to
>>>
>>>     be_pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream
>>>
>>> being NULL, hence when trying to set rtd a few lines below we get an
>oops.
>> It is a good practice to add the oops here
>
>Will this really be helpful? I think it'll be more clutter (the 
>backtrace on metag arch is not great):

I suspect you don't have frame pointers enabled in your kernel config. That should improve the meaningfulness of the backtrace.

>
>Oops: err 8007 (Unknown fault) addr 00000008 [#1]
>  Modules linked in:
>  CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.18.0-rc4+ #1904
>  Workqueue: deferwq _deferred_probe_work_func
>  task: 4f030780 ti: 4f044000 task.ti: 4f044000
>   pt_regs @ 4f044388
>   SaveMask = 0x4041
>   Flags = 0x0008 (Znoc)
>   TXRPT = 0x00000000
>   PC = 0x402e6c58
>   A0StP = 0x4f044388     A1GbP = 0x60001000
>   A0FrP = 0x4f044110     A1LbP = 0x40000048
>   A0.2  = 0x00000000     A1.2  = 0x00000000
>   A0.3  = 0x40090000     A1.3  = 0x00000001
>   D0Re0 = 0x00000000     D1Re0 = 0x00000001
>   D0Ar6 = 0x00000000     D1Ar5 = 0x4b5c1a00
>   D0Ar4 = 0x4f044330     D1Ar3 = 0x405833a8
>   D0Ar2 = 0x4f1d7170     D1Ar1 = 0x4b5c25a0
>   D0FrT = 0x00000001     D1RtP = 0x402e6c20
>   D0.5  = 0x00000000     D1.5  = 0x4f1f65c4
>   D0.6  = 0x4f1f65c4     D1.6  = 0x4f1d0500
>   D0.7  = 0x00000001     D1.7  = 0x4f1e3e40
>
>  Call trace:
>  [<40410004>] _ieee80211_change_bss+0x1b4/0x220
>  [<400f8034>] _kernfs_add_one+0x10c/0x17c
>  [<400fa2b0>] ___kernfs_create_file+0x94/0xdc
>  [<402d8bf0>] _snd_soc_register_card+0x12b8/0x1380
>  [<400170e8>] ___request_region+0x58/0x150
>  [<402068b4>] _devres_add+0x14/0x2c
>  [<402e97f0>] _zero1xx_probe+0x2b8/0x37c
>  [<40205004>] _platform_drv_probe+0x4c/0xc0
>  [<40204fb4>] _platform_drv_remove+0x3c/0x40
>  [<402032e0>] _driver_probe_device+0xc8/0x294
>  [<40204fb4>] _platform_drv_remove+0x3c/0x40
>  [<40203624>] _wait_for_device_probe+0x7c/0x80
>  [<40201cac>] _bus_for_each_drv+0x5c/0xb0
>  [<40203708>] _device_attach+0x84/0x9c
>  [<40202258>] _bus_probe_device+0x90/0xd0
>  [<4020354c>] _deferred_probe_work_func+0x70/0xac
>  [<40025d84>] _process_one_work+0x110/0x364
>  [<402034d8>] _device_bind_driver+0x2c/0x30
>  [<40046150>] _mod_timer+0xc4/0x178
>  [<400286a4>] _worker_thread+0x14c/0x4d4
>  [<4002b90c>] _kthread_parkme+0x14/0x18
>  [<40028554>] _pool_mayday_timeout+0xe8/0xec
>  [<4002ba08>] _kthread+0xf8/0x100
>  [<4000aeb4>] _ret_from_fork+0x44/0x110
>  [<4002b90c>] _kthread_parkme+0x14/0x18
>  [<40000044>] _text+0x44/0x48
>  [<40000044>] _text+0x44/0x48
>  [<4002b90c>] _kthread_parkme+0x14/0x18
>
>  Process: kworker/u2:0 (pid: 6, stack limit = 4f046000)
>  ---[ end trace fabdbb359f5c60d8 ]---


--
James Hogan