From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754083Ab1ASLrP (ORCPT ); Wed, 19 Jan 2011 06:47:15 -0500 Received: from 84-16-211.226.3p.ntebredband.no ([84.16.211.226]:46048 "EHLO mail.aptomar.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753911Ab1ASLrN (ORCPT ); Wed, 19 Jan 2011 06:47:13 -0500 Date: Wed, 19 Jan 2011 12:47:02 +0100 (CET) From: Rune Saetre X-X-Sender: rst@pingle.local.rsnet To: linux-kernel@vger.kernel.org cc: Patrik Jakobsson , Hans Verkuil , Rune Saetre , linux-media@vger.kernel.org In-Reply-To: <4D36B81B.9000602@gmail.com> Message-ID: References: <4D35BC4B.50108@gmail.com> <201101181730.52239.hverkuil@xs4all.nl> <4D36B81B.9000602@gmail.com> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="279707905-1434398323-1295437622=:15860" X-SA-Exim-Connect-IP: 84.16.211.227 X-SA-Exim-Mail-From: rune.saetre@aptomar.com Subject: Re: PROBLEM: kernel BUG at drivers/media/video/em28xx/em28xx-video.c:891 X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:20:07 +0000) X-SA-Exim-Scanned: Yes (on mail.aptomar.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --279707905-1434398323-1295437622=:15860 Content-Type: TEXT/PLAIN; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Hi Yes. I will try it out and post a message as soon as I have some=20 experience with it. Regards Rune --=20 We are proud to present our new web-pages at www.aptomar.com Do not miss our video-window to the world; aptotube Rune S=E6tre aptomar as Tel.=A0=A0 (+47) 40 00 34 03 Mob. (+47) 93 43 42 85 Fax=A0=A0=A0 (+47) 73 51 00 84 www.aptomar.com On Wed, 19 Jan 2011, Patrik Jakobsson wrote: > On 01/18/2011 05:30 PM, Hans Verkuil wrote: >> On Tuesday, January 18, 2011 17:14:03 Patrik Jakobsson wrote: >>> Hello Rune >>>=20 >>> I'm trying to learn more about the linux kernel so I figured helping >>> with bugs is a good way to get started. >>>=20 >>> On 01/18/2011 02:20 AM, Rune Saetre wrote: >>>> Hi >>>>=20 >>>> The crash is not as consistent as I first believed. I have managed to >>>> stop and start capturing several (but not many) times without the >>>> driver crashing now. >>>>=20 >>> To me it seems that the resource locking (functions res_get, res_check, >>> res_locked and res_free) is subject to race condition. >>>=20 >>> I looked at older versions of the code and found that there used to be >>> locks around some of these pieces. It was removed in commit: >>>=20 >>> 0499a5aa777f8e56e46df362f0bb9d9d116186f9 - V4L/DVB: em28xx: remove BKL >>>=20 >>> Other V4L drivers use pretty much the same code (res_get, res_free, >>> etc.) for resource locking but still have the mutex_lock/unlock around >>> it. Does anyone know why this was removed? >> Because now the video4linux core does the locking. >>=20 >> Anyway, I'm pretty sure this is the bug that was fixed here: >>=20 >> http://www.mail-archive.com/linuxtv-commits@linuxtv.org/msg09413.html >>=20 >> This fix will be in 2.6.38. >>=20 >> The change in the locking mechanism had nothing to do this particular bu= g. >> It was just incorrect administration of resources. >>=20 >> Regards, >> >> =09Hans >>=20 > Thanks for the explanation. I see now how the V4L core locks around the= =20 > ioctls. The member unlocked_ioctl of struct v4l2_file_operations confused= me=20 > a little. Maybe serialized_ioctl would be a better name? Not a big issue= =20 > though. > > Hopefully the patch fixes your problem Rune. > > Thanks > Patrik Jakobsson > >>> Thanks >>> Patrik Jakobsson >>>> The trace logs also differ slightly. Here is the last one: >>>>=20 >>>> Jan 18 02:12:08 mate kernel: [ 117.219326] ------------[ cut here >>>> ]------------ >>>> Jan 18 02:12:08 mate kernel: [ 117.219412] kernel BUG at >>>> drivers/media/video/em28xx/em28xx-video.c:891! >>>> Jan 18 02:12:08 mate kernel: [ 117.219507] invalid opcode: 0000 [#1] >>>> PREEMPT SMP Jan 18 02:12:08 mate kernel: [ 117.219597] last sysfs >>>> file: /sys/devices/virtual/block/dm-8/stat >>>> Jan 18 02:12:08 mate kernel: [ 117.219681] CPU 1 Jan 18 02:12:08 mate >>>> kernel: [ 117.219714] Modules linked in: acpi_cpufreq mperf >>>> cpufreq_powersave cpufreq_stats cpufreq_userspace cpufreq_conservative >>>> ppdev lp nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs binfmt_misc >>>> fuse dummy bridge stp ext2 mbcache coretemp kvm_intel kvm loop >>>> firewire_sbp2 tuner snd_hda_codec_realtek arc4 snd_hda_intel >>>> snd_usb_audio snd_hda_codec ecb snd_seq_dummy snd_pcm_oss >>>> snd_mixer_oss saa7115 snd_pcm ir_lirc_codec lirc_dev ir_sony_decoder >>>> snd_hwdep snd_usbmidi_lib em28xx ir_jvc_decoder ir_rc6_decoder >>>> snd_seq_oss snd_seq_midi snd_rawmidi r8169 ir_rc5_decoder mii >>>> ir_nec_decoder snd_seq_midi_event i915 v4l2_common iwlagn iwlcore >>>> snd_seq ir_core drm_kms_helper drm videobuf_vmalloc snd_timer >>>> snd_seq_device videobuf_core pcmcia joydev mac80211 uvcvideo videodev >>>> v4l1_compat v4l2_compat_ioctl32 tveeprom cfg80211 rfkill i2c_i801 >>>> i2c_algo_bit tpm_tis tpm yenta_socket snd intel_agp shpchp pci_hotplug >>>> video output pcmcia_rsrc wmi pcmcia_core soundcore snd_page_alloc >>>> parport_pc parport i2c_cor >>>> Jan 18 02:12:08 mate kernel: irda tpm_bios intel_gtt pcspkr crc_ccitt >>>> psmouse evdev serio_raw container processor battery ac button reiserfs >>>> dm_mod raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor >>>> xor async_memcpy async_tx raid1 raid0 multipath linear md_mod >>>> ide_cd_mod cdrom sd_mod ata_generic pata_acpi ata_piix crc_t10dif >>>> ide_pci_generic ahci libahci sdhci_pci firewire_ohci sdhci libata >>>> scsi_mod piix ide_core firewire_core mmc_core uhci_hcd tg3 thermal >>>> crc_itu_t thermal_sys ehci_hcd [last unloaded: scsi_wait_scan] >>>> Jan 18 02:12:08 mate kernel: [ 117.220091] Jan 18 02:12:08 mate >>>> kernel: [ 117.220091] Pid: 3154, comm: camera_factory_ Not tainted >>>> 2.6.37-rst #1 Victoria /TravelMate 6292 Jan 18 02:12:08 mate >>>> kernel: [ 117.220091] RIP: 0010:[] >>>> [] res_free+0x14/0x49 [em28xx] >>>> Jan 18 02:12:08 mate kernel: [ 117.220091] RSP: >>>> 0018:ffff8800794a1c48 EFLAGS: 00010297 >>>> Jan 18 02:12:08 mate kernel: [ 117.220091] RAX: 0000000000000001 RBX: >>>> ffff88007b94dc00 RCX: 0000000000000000 >>>> Jan 18 02:12:08 mate kernel: [ 117.220091] RDX: 0000000000000000 RSI: >>>> ffff8800378e7000 RDI: ffff88007b94dc00 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] RBP: ffff8800378e7000 R08: >>>> 0000000000000001 R09: 0000000000000c52 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] R10: 0000000000000000 R11: >>>> 0000000000000246 R12: 0000000000000000 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] R13: ffffffffa05ab920 R14: >>>> ffff88006dd123c0 R15: ffff88007b94dc00 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] FS: >>>> 00007f37105bb820(0000) GS:ffff88007f500000(0000) knlGS:000000000000000= 0 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] CS: 0010 DS: 0000 ES: >>>> 0000 CR0: 0000000080050033 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] CR2: 000000000378b248 CR3: >>>> 000000007a079000 CR4: 00000000000006e0 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] DR0: 0000000000000000 DR1: >>>> 0000000000000000 DR2: 0000000000000000 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] DR3: 0000000000000000 DR6: >>>> 00000000ffff0ff0 DR7: 0000000000000400 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] Process camera_factory_ >>>> (pid: 3154, threadinfo ffff8800794a0000, task ffff880071f6d820) >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] Stack: >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] ffff8800378e7000 >>>> ffffffffa05a46b9 ffff88007a2fd040 ffffffff81042cf3 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] 0000000000000001 >>>> ffffffff00000001 ffffffff8103dadb 0000000000000001 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] ffff88007ba3e400 >>>> ffffffffa03302ff 00000000000135c0 00000000000135c0 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] Call Trace: >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> vidioc_streamoff+0xa6/0xb6 [em28xx] >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> get_parent_ip+0x9/0x1b >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> need_resched+0x1a/0x23 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> __video_do_ioctl+0x12e2/0x33a0 [videodev] >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> __wake_up_common+0x41/0x78 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> __wake_up+0x35/0x46 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> get_parent_ip+0x9/0x1b >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> add_preempt_count+0x9e/0xa0 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> _raw_spin_lock_irqsave+0x40/0x61 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> video_ioctl2+0x2ad/0x35d [videodev] >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> get_parent_ip+0x9/0x1b >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> v4l2_ioctl+0x74/0x113 [videodev] >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> do_vfs_ioctl+0x418/0x465 >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> sys_ioctl+0x3c/0x5e >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] [] ? >>>> system_call_fastpath+0x16/0x1b >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] Code: 03 4c 39 e3 0f 18 08 >>>> 75 d4 31 c0 eb 05 b8 ea ff ff ff 5b 5d 41 5c c3 48 83 ec 08 8b 57 0c >>>> 89 f0 89 c1 48 8b 37 21 d1 39 c1 74 04<0f> 0b eb fe 89 c8 f7 d0 21 c2 >>>> 89 57 0c 21 86 d0 09 00 00 83 3d Jan 18 02:12:09 mate kernel: [ >>>> 117.220091] RIP [] res_free+0x14/0x49 [em28xx] >>>> Jan 18 02:12:09 mate kernel: [ 117.220091] RSP >>>> Jan 18 02:12:09 mate kernel: [ 117.264998] ---[ end trace >>>> 6d6576ecd99356c8 ]--- >>>>=20 >>>> I hope this helps. >>>>=20 >>>> Regards >>>> Rune >>>>=20 >>>>=20 >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-media" = in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>=20 > > --279707905-1434398323-1295437622=:15860--