I saw this too, while working with Antti on adding support for another rtl2832-based DVB card. The kernel version [ 0.000000] Linux version 3.13.0-45-generic (buildd@kissel) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #74-Ubuntu SMP Tue Jan 13 19:37:48 UTC 2015 (Ubuntu 3.13.0-45.74-generic 3.13.11-ckt13) This is what dmesg contained: [ 247.897962] BUG: unable to handle kernel NULL pointer dereference at 00000008 [ 247.897971] IP: [<f84f62f4>] media_entity_pipeline_start+0x24/0x350 [media] [ 247.897982] *pdpt = 000000001c70f001 *pde = 0000000000000000 [ 247.897988] Oops: 0000 [#1] SMP [ 247.897992] Modules linked in: gpio_ich nvidia(POX) snd_hda_codec_hdmi bnep ir_lirc_codec(OX) rfcomm ir_xmp_decoder(OX) lirc_dev(OX) ir_sony_decoder(OX) ir_sharp_decoder(OX) ir_sanyo_decoder(OX) ir_rc6_decoder(OX) ir_rc5_decoder(OX) ir_nec_decoder(OX) ir_mce_kbd_decoder(OX) ir_jvc_decoder(OX) bluetooth rtl2832_sdr(OX) videobuf2_vmalloc(OX) snd_hda_intel videobuf2_memops(OX) snd_intel8x0 snd_ac97_codec snd_hda_codec videobuf2_core(OX) ac97_bus snd_hwdep v4l2_common(OX) snd_pcm videodev(OX) snd_page_alloc fc0013(OX) snd_seq_midi snd_seq_midi_event rtl2832(OX) snd_rawmidi i2c_mux snd_seq dvb_usb_rtl28xxu(OX) dvb_usb_v2(OX) dvb_core(OX) rc_core(OX) snd_seq_device media(OX) snd_timer dcdbas snd serio_raw drm soundcore lpc_ich shpchp ppdev parport_pc lp mac_hid parport hid_generic tg3 usbhid psmouse ptp e1000 pps_core pata_acpi floppy hid [ 247.898043] CPU: 0 PID: 2967 Comm: kdvb-ad-0-fe-0 Tainted: POX 3.13.0-45-generic #74-Ubuntu [ 247.898046] Hardware name: Dell Inc. OptiPlex GX280/0DG476, BIOS A07 11/29/2005 [ 247.898049] task: e5e9db00 ti: dbb80000 task.ti: dbb80000 [ 247.898052] EIP: 0060:[<f84f62f4>] EFLAGS: 00010286 CPU: 0 [ 247.898058] EIP is at media_entity_pipeline_start+0x24/0x350 [media] [ 247.898061] EAX: 00000000 EBX: e0b26280 ECX: f7b8a580 EDX: f6aac614 [ 247.898063] ESI: f6aac400 EDI: 00000000 EBP: dbb81f08 ESP: dbb81e30 [ 247.898066] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 247.898069] CR0: 8005003b CR2: 00000008 CR3: 1c70e000 CR4: 000007f0 [ 247.898072] Stack: [ 247.898074] f7b8a5c8 00000001 00000006 00000000 b7de1fcc 00000039 00000000 00000001 [ 247.898081] 00000000 f7b8a5c8 00000001 00000000 dbb81eb4 c1089ef6 dbb81eb8 c108c7c9 [ 247.898086] 00000000 f7b8a580 f7b8a5c8 f7b8a580 f261ea00 e5e9db00 dbb81eac c108a44a [ 247.898093] Call Trace: [ 247.898102] [<c1089ef6>] ? dequeue_task_fair+0x416/0x7c0 [ 247.898106] [<c108c7c9>] ? enqueue_task_fair+0x5d9/0x7e0 [ 247.898110] [<c108a44a>] ? check_preempt_wakeup+0x1aa/0x250 [ 247.898115] [<c1087b21>] ? set_next_entity+0xb1/0xe0 [ 247.898120] [<c100ed20>] ? __switch_to+0xb0/0x340 [ 247.898126] [<c1658fc8>] ? __schedule+0x358/0x770 [ 247.898130] [<c1082c60>] ? try_to_wake_up+0x150/0x240 [ 247.898143] [<f8763121>] dvb_frontend_thread+0x331/0x9a0 [dvb_core] [ 247.898154] [<f8763121>] ? dvb_frontend_thread+0x331/0x9a0 [dvb_core] [ 247.898158] [<c1082dc0>] ? default_wake_function+0x10/0x20 [ 247.898162] [<c1090f57>] ? __wake_up_common+0x47/0x70 [ 247.898166] [<c1090f9f>] ? __wake_up_locked+0x1f/0x30 [ 247.898177] [<f8762df0>] ? dvb_frontend_ioctl_legacy.isra.8+0xc20/0xc20 [dvb_core] [ 247.898182] [<c10751d1>] kthread+0xa1/0xc0 [ 247.898187] [<c1663b37>] ret_from_kernel_thread+0x1b/0x28 [ 247.898191] [<c1075130>] ? kthread_create_on_node+0x140/0x140 [ 247.898193] Code: 90 90 90 90 90 90 90 57 8d 7c 24 08 83 e4 f8 ff 77 fc 55 89 e5 57 56 53 81 ec cc 00 00 00 3e 8d 74 26 00 89 c7 89 85 48 ff ff ff <8b> 40 08 89 95 50 ff ff ff 89 85 60 ff ff ff 05 44 02 00 00 89 [ 247.898229] EIP: [<f84f62f4>] media_entity_pipeline_start+0x24/0x350 [media] SS:ESP 0068:dbb81e30 [ 247.898236] CR2: 0000000000000008 [ 247.898241] ---[ end trace 800df23615d3c02a ]--- The git commit for the media_build tree at the time I compiled everything was commit c40e87b410c9ed170e2ae6ca2aeef06a44621b20 Add writel_relaxed supportHEADmaster Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> HTH Vince -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
