Hi, Lately, when experimenting with JACK, I began getting kernel crashes :( The platform is a Dell Precision M6600 mobile workstation, and currently I am using the built-in sound. (These are just experiments; I intend to use a different audio device for the final configuration.) I am using stock Debian kernel v3.1.5. The kernel log looks like this: ----------------------------------------------------------------------- [ 7555.763914] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 [ 7555.763952] IP: [<ffffffffa08ca7b8>] setup_bdle.isra.21+0x44/0xd9 [snd_hda_intel] [ 7555.763984] PGD 203005067 PUD 203004067 PMD 0 [ 7555.764005] Oops: 0000 [#1] SMP [ 7555.764021] CPU 3 [ 7555.764029] Modules linked in: snd_hda_codec_hdmi snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device snd soundcore snd_page_alloc xt_limit xt_tcpudp ipt_LOG ipt_MASQUERADE xt_DSCP ipt_REJECT nf_conntrack_irc nf_conntrack_ftp xt_state acpi_cpufreq cpufreq_stats mperf cpufreq_conservative cpufreq_userspace cpufreq_powersave ppdev lp rfcomm bnep bluetooth pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) binfmt_misc uinput fuse nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_mangle iptable_filter ip_tables x_tables loop firewire_sbp2 uvcvideo videodev media v4l2_compat_ioctl32 arc4 brcmsmac(C) radeon ttm mac80211 drm_kms_helper dell_laptop drm brcmutil(C) i2c_algo_bit cfg80211 iTCO_wdt i2c_i801 dcdbas battery ac iTCO_vendor_support video processor button rfkill i2c_core pcspkr evdev psmouse serio_raw dell_wmi sparse_keymap power_supply parport_pc wmi parport ext4 mbcache jbd2 crc16 sha256_generic aesni_intel cryptd aes_x86_64 aes_generic cbc dm_crypt dm_mod raid1 md_mod sr_mod cdrom sd_mod crc_t10dif ehci_hcd xhci_hcd thermal thermal_sys ahci libahci libata firewire_ohci scsi_mod sdhci_pci sdhci mmc_core firewire_core crc_itu_t usbcore e1000e [last unloaded: scsi_wait_scan] [ 7555.764630] [ 7555.764637] Pid: 13399, comm: jackd Tainted: G C O 3.1.0-1-amd64 #1 Dell Inc. Precision M6600/04YY4M [ 7555.764677] RIP: 0010:[<ffffffffa08ca7b8>] [<ffffffffa08ca7b8>] setup_bdle.isra.21+0x44/0xd9 [snd_hda_intel] [ 7555.764715] RSP: 0018:ffff88020bce1c98 EFLAGS: 00010293 [ 7555.764735] RAX: 0000000000000000 RBX: ffff880221825e00 RCX: 0000000000000000 [ 7555.764761] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880221825e00 [ 7555.764787] RBP: ffff8801e1339240 R08: 0000000000000008 R09: 0000000000000001 [ 7555.764813] R10: ffff8802239884d8 R11: ffff8802239884d8 R12: 0000000000000000 [ 7555.764838] R13: ffff88020bce1d10 R14: ffff8802031c7000 R15: 0000000000000008 [ 7555.764865] FS: 00007f991600a700(0000) GS:ffff88022dc60000(0000) knlGS:0000000000000000 [ 7555.764894] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7555.764915] CR2: 0000000000000028 CR3: 000000021b07d000 CR4: 00000000000406e0 [ 7555.764941] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 7555.764967] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 7555.764993] Process jackd (pid: 13399, threadinfo ffff88020bce0000, task ffff880221ae69b0) [ 7555.765023] Stack: [ 7555.765031] 0000000000001f51 ffffffffa08aae4a ffff8801e1339200 ffff88022337bc00 [ 7555.765063] ffff880221825e00 ffff8802033cc800 ffff8801fcab8500 ffffffffa08caa5c [ 7555.765094] 0000200000000092 ffff8801f2cd5230 ffff8801e1339258 000000022337bd28 [ 7555.765126] Call Trace: [ 7555.765139] [<ffffffffa08aae4a>] ? snd_hda_calc_stream_format+0x56/0xc0 [snd_hda_codec] [ 7555.765170] [<ffffffffa08caa5c>] ? azx_pcm_prepare+0x20f/0x3c7 [snd_hda_intel] [ 7555.765198] [<ffffffffa088146e>] ? snd_pcm_do_prepare+0xe/0x1f [snd_pcm] [ 7555.765225] [<ffffffffa0881028>] ? snd_pcm_action_single+0x26/0x5b [snd_pcm] [ 7555.765253] [<ffffffff8103538b>] ? should_resched+0x5/0x23 [ 7555.765276] [<ffffffff8132c4b7>] ? _cond_resched+0x7/0x1c [ 7555.765298] [<ffffffffa0881147>] ? snd_pcm_action_nonatomic+0x48/0x62 [snd_pcm] [ 7555.765326] [<ffffffffa0881d6b>] ? snd_pcm_common_ioctl1+0x3c2/0xa8f [snd_pcm] [ 7555.765354] [<ffffffff8119e944>] ? __rwsem_do_wake+0xa4/0x162 [ 7555.765376] [<ffffffff8119ea77>] ? rwsem_wake+0x36/0x3f [ 7555.765398] [<ffffffffa08828ac>] ? snd_pcm_playback_ioctl1+0x21a/0x22d [snd_pcm] [ 7555.765426] [<ffffffff8106202d>] ? up_read+0x13/0x14 [ 7555.765446] [<ffffffff8133076a>] ? do_page_fault+0x2fc/0x337 [ 7555.765469] [<ffffffffa08828e6>] ? snd_pcm_playback_ioctl+0x27/0x2c [snd_pcm] [ 7555.765497] [<ffffffffa08828bf>] ? snd_pcm_playback_ioctl1+0x22d/0x22d [snd_pcm] [ 7555.765525] [<ffffffff81100f94>] ? do_vfs_ioctl+0x452/0x493 [ 7555.765546] [<ffffffff81101020>] ? sys_ioctl+0x4b/0x6f [ 7555.765567] [<ffffffff81332792>] ? system_call_fastpath+0x16/0x1b [ 7555.765589] Code: 8b 32 e9 94 00 00 00 81 7d 00 ff 00 00 00 0f 87 96 00 00 00 48 8b 83 c0 00 00 00 44 89 e2 44 89 e6 48 89 df 48 8b 80 d8 02 00 00 [ 7555.765683] 8b 48 28 48 89 d0 81 e2 ff 0f 00 00 48 c1 e8 0c 48 c1 e0 04 [ 7555.765730] RIP [<ffffffffa08ca7b8>] setup_bdle.isra.21+0x44/0xd9 [snd_hda_intel] [ 7555.765760] RSP <ffff88020bce1c98> [ 7555.765773] CR2: 0000000000000028 [ 7555.775195] ---[ end trace 25953054946e6aac ]--- ----------------------------------------------------------------------- This is probably a kernel error, but the only thing that triggers this for me is JACK. (Others have seen this with Sype, kernel v2.6.38 and kernel v2.6.40, in Fedora, on various Dell, Acer and Samsung devices https://bugzilla.redhat.com/show_bug.cgi?id=702056 https://bugzilla.redhat.com/show_bug.cgi?id=718056 https://bugzilla.redhat.com/show_bug.cgi?id=749186 ) Do you have any idea how to avoid this? Thank you: Kristof