Game causes NULL pointer dereference in kernel

[afalkenhahn]

I have a game that runs fine on x86 Linux but when compiling it for ARM on my Raspberry Pi 2, it often crashes the whole operating system. The issue seems to be related to the ALSA driver because it only occurs when sound is enabled in the game. No sound, no crashes.

Here is what var/log/syslog looks like after a crash. The interesting thing is probably at 13:29:32 because it is reporting Unable to handle kernel NULL pointer dereference at virtual address 00000000 at this point which could be related to #621.

Jul 10 13:26:37 raspberrypi kernel: [   58.723345] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:26:37 raspberrypi kernel: [   58.723388] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:26:47 raspberrypi kernel: [   68.566732] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:26:47 raspberrypi kernel: [   68.566756] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:26:47 raspberrypi kernel: [   68.568377] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:04 raspberrypi kernel: [   84.908452] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:05 raspberrypi kernel: [   85.988429] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:05 raspberrypi kernel: [   85.988455] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:05 raspberrypi kernel: [   85.988490] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:08 raspberrypi kernel: [   88.852333] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:21 raspberrypi kernel: [  102.173166] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:23 raspberrypi kernel: [  104.296299] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:23 raspberrypi kernel: [  104.296777] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:24 raspberrypi kernel: [  105.071317] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:24 raspberrypi kernel: [  105.071345] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:24 raspberrypi kernel: [  105.071782] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:24 raspberrypi kernel: [  105.071813] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:24 raspberrypi kernel: [  105.226809] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:24 raspberrypi kernel: [  105.227236] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:24 raspberrypi kernel: [  105.557247] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:24 raspberrypi kernel: [  105.557448] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:24 raspberrypi kernel: [  105.557478] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:24 raspberrypi kernel: [  105.557501] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:24 raspberrypi kernel: [  105.701905] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:25 raspberrypi kernel: [  105.845243] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:25 raspberrypi kernel: [  105.845268] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:25 raspberrypi kernel: [  105.845339] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:25 raspberrypi kernel: [  105.845369] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:25 raspberrypi kernel: [  105.845462] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:25 raspberrypi kernel: [  105.845491] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:25 raspberrypi kernel: [  105.845514] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:25 raspberrypi kernel: [  105.954211] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:25 raspberrypi kernel: [  105.954827] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:25 raspberrypi kernel: [  106.058414] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:25 raspberrypi kernel: [  106.058440] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:25 raspberrypi kernel: [  106.058474] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:25 raspberrypi kernel: [  106.058498] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:25 raspberrypi kernel: [  106.426792] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:25 raspberrypi kernel: [  106.426838] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:25 raspberrypi kernel: [  106.571810] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:42 raspberrypi kernel: [  123.087638] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:43 raspberrypi kernel: [  124.494882] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:43 raspberrypi kernel: [  124.494935] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:43 raspberrypi kernel: [  124.494962] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:43 raspberrypi kernel: [  124.651874] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:43 raspberrypi kernel: [  124.651913] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:43 raspberrypi kernel: [  124.794293] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:44 raspberrypi kernel: [  124.954301] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:44 raspberrypi kernel: [  124.954904] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:44 raspberrypi kernel: [  124.954945] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:44 raspberrypi kernel: [  125.104276] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:44 raspberrypi kernel: [  125.261245] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:44 raspberrypi kernel: [  125.261272] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:44 raspberrypi kernel: [  125.390072] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:45 raspberrypi kernel: [  125.992627] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:45 raspberrypi kernel: [  125.992673] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:27:45 raspberrypi kernel: [  126.582654] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:27:45 raspberrypi kernel: [  126.582682] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:27:58 raspberrypi kernel: [  139.324682] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:27:58 raspberrypi kernel: [  139.534663] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:11 raspberrypi kernel: [  152.097032] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:17 raspberrypi kernel: [  158.224712] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:17 raspberrypi kernel: [  158.224755] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  159.963772] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:19 raspberrypi kernel: [  159.963817] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:19 raspberrypi kernel: [  159.963843] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  159.964184] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  160.124924] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:19 raspberrypi kernel: [  160.279402] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:19 raspberrypi kernel: [  160.279726] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:19 raspberrypi kernel: [  160.279758] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:19 raspberrypi kernel: [  160.279781] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  160.426672] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:28:19 raspberrypi kernel: [  160.426698] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:19 raspberrypi kernel: [  160.426801] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:19 raspberrypi kernel: [  160.426835] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  160.427258] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:19 raspberrypi kernel: [  160.574714] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:28:19 raspberrypi kernel: [  160.574739] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:19 raspberrypi kernel: [  160.574772] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:19 raspberrypi kernel: [  160.725709] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:20 raspberrypi kernel: [  160.835947] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:28:20 raspberrypi kernel: [  160.835971] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:20 raspberrypi kernel: [  160.836439] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:20 raspberrypi kernel: [  160.926598] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:28:20 raspberrypi kernel: [  160.926622] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:20 raspberrypi kernel: [  160.926659] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:20 raspberrypi kernel: [  160.926815] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:20 raspberrypi kernel: [  161.454756] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:28:20 raspberrypi kernel: [  161.454782] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:28:20 raspberrypi kernel: [  161.749707] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:28:20 raspberrypi kernel: [  161.749752] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:28:59 raspberrypi kernel: [  200.001649] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:29:19 raspberrypi kernel: [  219.861713] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:29:20 raspberrypi kernel: [  221.076686] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:29:25 raspberrypi kernel: [  226.166698] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:29:26 raspberrypi kernel: [  227.191703] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:29:32 raspberrypi kernel: [  233.249388] Unable to handle kernel NULL pointer dereference at virtual address 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.255890] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:29:32 raspberrypi kernel: [  233.255897] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:29:32 raspberrypi kernel: [  233.255924] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:29:32 raspberrypi kernel: [  233.256710] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:29:32 raspberrypi kernel: [  233.257505] pgd = 80004000
Jul 10 13:29:32 raspberrypi kernel: [  233.260208] [00000000] *pgd=00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.261711] bcm2835_audio_set_params:583  Alsa controls not supported
Jul 10 13:29:32 raspberrypi kernel: [  233.261716] snd_bcm2835_pcm_prepare:329  error setting hw params
Jul 10 13:29:32 raspberrypi kernel: [  233.261739] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 0
Jul 10 13:29:32 raspberrypi kernel: [  233.263612] 
Jul 10 13:29:32 raspberrypi kernel: [  233.263806] Internal error: Oops: 5 [#1] SMP ARM
Jul 10 13:29:32 raspberrypi kernel: [  233.265888] bcm2835_audio_set_ctls:556 Couldn't set the controls for stream 1
Jul 10 13:29:32 raspberrypi kernel: [  233.275537] Modules linked in: arc4 ecb md4 md5 hmac nls_utf8 cifs snd_bcm2835 snd_pcm snd_seq snd_seq_device snd_timer snd bcm2835_gpiomem bcm2835_wdt evdev joydev uio_pdrv_genirq uio
Jul 10 13:29:32 raspberrypi kernel: [  233.292104] CPU: 1 PID: 70 Comm: VCHIQ-0 Not tainted 4.4.14-v7+ #896
Jul 10 13:29:32 raspberrypi kernel: [  233.298450] Hardware name: BCM2709
Jul 10 13:29:32 raspberrypi kernel: [  233.301849] task: b9081140 ti: b9068000 task.ti: b9068000
Jul 10 13:29:32 raspberrypi kernel: [  233.307256] PC is at __wake_up_common+0x30/0x90
Jul 10 13:29:32 raspberrypi kernel: [  233.311787] LR is at __wake_up_locked+0x24/0x2c
Jul 10 13:29:32 raspberrypi kernel: [  233.316319] pc : [<80063238>]    lr : [<800632bc>]    psr: a0050093
Jul 10 13:29:32 raspberrypi kernel: [  233.316319] sp : b9069e18  ip : b9069e48  fp : b9069e44
Jul 10 13:29:32 raspberrypi kernel: [  233.327788] r10: 00000001  r9 : 00000003  r8 : 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.327794] r7 : 00000000  r6 : b7612118  r5 : b7612110  r4 : b7612114
Jul 10 13:29:32 raspberrypi kernel: [  233.327799] r3 : 00000000  r2 : 00000001  r1 : 00000000  r0 : b7612114
Jul 10 13:29:32 raspberrypi kernel: [  233.327808] Flags: NzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Jul 10 13:29:32 raspberrypi kernel: [  233.327833] Control: 10c5387d  Table: 389d006a  DAC: 00000055
Jul 10 13:29:32 raspberrypi kernel: [  233.327840] Process VCHIQ-0 (pid: 70, stack limit = 0xb9068210)
Jul 10 13:29:32 raspberrypi kernel: [  233.327848] Stack: (0xb9069e18 to 0xb906a000)
Jul 10 13:29:32 raspberrypi kernel: [  233.327856] 9e00:                                                       00000000 b7612114
Jul 10 13:29:32 raspberrypi kernel: [  233.327868] 9e20: b7612110 60050013 00000000 b9341200 bac91c90 8095ea64 b9069e5c b9069e48
Jul 10 13:29:32 raspberrypi kernel: [  233.327880] 9e40: 800632bc 80063214 00000000 b7612110 b9069e7c b9069e60 80063b60 800632a4
Jul 10 13:29:32 raspberrypi kernel: [  233.327890] 9e60: 00000000 b7612100 00000000 bac91c90 b9069eb4 b9069e80 7f07be9c 80063b28
Jul 10 13:29:32 raspberrypi kernel: [  233.327902] 9e80: 00000000 b9341200 00000014 00000000 00000000 3df6e9bc 3dfaef04 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.327913] 9ea0: b75e6900 00000002 b9069ed4 b9069eb8 803d4154 7f07bde8 00000020 803d4080
Jul 10 13:29:32 raspberrypi kernel: [  233.327924] 9ec0: 45043003 808a7f1c b9069f5c b9069ed8 803cc800 803d408c 00000000 80875408
Jul 10 13:29:32 raspberrypi kernel: [  233.327935] 9ee0: 808618c4 b9081424 b9069f44 b9069ef8 805b4d08 8004988c fff9fee9 b9911ccc
Jul 10 13:29:32 raspberrypi kernel: [  233.327947] 9f00: 805ed708 bac80194 bac80020 00000014 000c9cb0 00000003 00000014 bac80194
Jul 10 13:29:32 raspberrypi kernel: [  233.327958] 9f20: fff9fee9 ffffffff 00000000 00000000 00000000 00000000 b906b8c0 8095ea64
Jul 10 13:29:32 raspberrypi kernel: [  233.327970] 9f40: 803cb8f8 00000000 00000000 00000000 b9069fac b9069f60 80042678 803cb904
Jul 10 13:29:32 raspberrypi kernel: [  233.327981] 9f60: 39718000 00000000 00000000 8095ea64 00000000 00000000 b9069f78 b9069f78
Jul 10 13:29:32 raspberrypi kernel: [  233.327992] 9f80: 00000000 00000000 b9069f88 b9069f88 b906b8c0 8004258c 00000000 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.328002] 9fa0: 00000000 b9069fb0 8000fbc8 80042598 00000000 00000000 00000000 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.328013] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.328023] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
Jul 10 13:29:32 raspberrypi kernel: [  233.328059] [<80063238>] (__wake_up_common) from [<800632bc>] (__wake_up_locked+0x24/0x2c)
Jul 10 13:29:32 raspberrypi kernel: [  233.328077] [<800632bc>] (__wake_up_locked) from [<80063b60>] (complete+0x44/0x54)
Jul 10 13:29:32 raspberrypi kernel: [  233.328118] [<80063b60>] (complete) from [<7f07be9c>] (audio_vchi_callback+0xc0/0x130 [snd_bcm2835])
Jul 10 13:29:32 raspberrypi kernel: [  233.328161] [<7f07be9c>] (audio_vchi_callback [snd_bcm2835]) from [<803d4154>] (shim_callback+0xd4/0x118)
Jul 10 13:29:32 raspberrypi kernel: [  233.328182] [<803d4154>] (shim_callback) from [<803cc800>] (slot_handler_func+0xf08/0x1858)
Jul 10 13:29:32 raspberrypi kernel: [  233.328199] [<803cc800>] (slot_handler_func) from [<80042678>] (kthread+0xec/0x104)
Jul 10 13:29:32 raspberrypi kernel: [  233.328219] [<80042678>] (kthread) from [<8000fbc8>] (ret_from_fork+0x14/0x2c)
Jul 10 13:29:32 raspberrypi kernel: [  233.328233] Code: e1a0a002 e1a08003 e1560001 e59b7004 (e5914000) 
Jul 10 13:29:32 raspberrypi kernel: [  233.328245] ---[ end trace b848eb8e41ea8852 ]--- 

I've tested this with the latest kernel (Linux raspberrypi 4.4.14-v7+ #896 SMP Sat Jul 2 15:09:43 BST 2016 armv7l GNU/Linux) on two different machines. They both aren't overclocked and run at 700mhz. So it shouldn't be a hardware fault.

When the error occurs it usually renders the system unusable. Even rebooting is often not possible any more after the error has occurred making this quite a nightmare to debug.

It only seems to happen when the sound driver is in a stress situation. Unfortunately, I wasn't able to isolate the problem so the only test program I can provide is the full game. You can grab it here: http://www.softwarefailure.de/tmp/demo.tar.gz (I'm sorry but it's a 70 MB file)

Just try to play the game and the kernel should crash pretty soon. Sometimes it takes a few minutes but normally it happens earlier.

[popcornmix]

I can run the game. Is it enough just to leave it on intro screen playing music to get the failure?
It ran for me until the game exited due to time limited demo (5 minutes I think?)

[afalkenhahn]

No, you need to play the game because it seems to occur when the sound driver is stressed, e.g. lots of sound fx are played and stopped, played and stopped, played and stopped again etc. There are no sound fx during the intro. So please play the game and it should show up.

[afalkenhahn]

Just out of curiosity, have you managed to reproduce the kernel crash on your system?

[popcornmix]

No. I've just played the game for two 5 minute sessions without seeing the hang.
Are you seeing the issue on a clean jessie install?
Are you using hdmi or analogue audio?

You mention using Pi2 and running at 700Mhz - are you explicitly underclocking?

[afalkenhahn]

Yes, my test system has a clean Jessie install. I've now tested analogue audio and actually it doesn't seem to occur with analogue audio. Only HDMI audio seems to trigger the crash. So please try with HDMI audio and it should be reproducable on your system too...

I'm running the Pi2 at 700mhz because that is the only speed where raspi-config says "None", i.e. no overclocking. So is raspi-config wrong here? What speed should I use for no overclocking instead?

[popcornmix]

I think you are looking at the Pi1 overclock settings (possibly raspi-config isn't very clear here).
Stock is 900MHz on Pi2.

[afalkenhahn]

Ok, I've now reverted it to 900Mhz. The crash, however, is still there but only when using HDMI. The kernel usually crashes pretty quickly when using HDMI. Also, there are some other audio glitches. When using analogue audio there are no glitches at all but with HDMI there is often a lag of 1 second before the audio can actually be heard. But of course the most annoying thing is that kernel crash because it takes down the whole machine.

[afalkenhahn]

Have you been able to reproduce the crash using HDMI audio?

[popcornmix]

Yes, I have reproduced.
Are you using any signal handlers in your code? What signals can occur?

[afalkenhahn]

Yes, I'm using two signal handlers: One for SIGRTMIN and one for SIGRTMIN+1. The code goes like this:

sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO;
sigact.sa_sigaction = Custom_SignalHandler;
sigaction(SIGRTMIN, &sigact, NULL);

Same for SIGRTMIN+1...

[popcornmix]

Can you try: https://dl.dropboxusercontent.com/u/3669512/temp/kernel7.img

[afalkenhahn]

After this update my keyboard and mouse don't work any longer in Raspbian and there is an error from libkmod at startup, "could not open moddep file" or something like this. How can I fix this? I did some googling but I can't really try out any of the suggested fixes because mouse and keyboard don't work at all so I can't really do anything. The only thing I can still access is the NOOBS recovery mode but it doesn't allow me to do anything except doing a complete reinstall :/

[popcornmix]

Okay, your modules are older than this kernel.
Running sudo rpi-update then copying the kernel would likely have worked.

Can you ssh in to Pi? I suspect ethernet will still be working as that doesn't require kernel modules?

[afalkenhahn]

Ok, ssh saved the day. After doing sudo rpi-update I was now able to try out the new kernel image. However, the problem is still there. Even worse, it seems to occur almost immediately now. With the old image I could often play for a few minutes before it happened, now it's just a few seconds before the kernel says goodbye...