Regression found in loopback.c patch (0cf833a)
Hello, I believe I have found a regression in drivers/net/loopback.c which was introduced starting with the v3.7 kernel series (and also affects v3.8). Oddly enough, it affects DVD playback (both physical disk and .iso files) in MythTV (I'm using v0.26 and compile from source). I don't know if MythTV mounts a .iso or DVD over a loopback device but for whatever reason there is a problem. When playing a DVD there is a constant stuttering of the video and corresponding audio dropouts. This is continual with mythfrontend logs showing "Waiting for video buffers." I found that any kernel before v3.7 did not cause this issue so I did a git bisect between v3.6 and v3.7. The resulting bisection was to commit 0cf833a (net: loopback: set default mtu to 64K). I downloaded the source to v3.7.9 and reverted the line: dev->mtu = 64 * 1024; back to: dev->mtu = (16 * 1024) + 20 + 20 + 12; The resulting kernel did not cause the playback stuttering. I have also compiled v3.8.0 using (16 * 1024) + 20 + 20 + 12; and again had no problems. Please let me know if you have any questions. Thank you, Neil Salstrom -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: 3.6.0 kernel BUG at fs/dcache.c:967 during shutdown / restart
On 10/08/2012 10:14 AM, Jan Kara wrote:
On Sat 06-10-12 10:20:26, Neil Salstrom wrote:
I've not submitted a kernel bug before but I've read the bug
reporting pages. I'll try to do my best and if you need more
information please let me know. Please feel free to cc me on the
answer or if you have questions.
I'm using Linux Mint 13 (64 bit) on AMD hardware with a self
compiled 3.6.0 kernel for my MythTV HTPC.
Kernel version: Linux version 3.6.0 (gcc version 4.6.3
(Ubuntu/Linaro 4.6.3-1ubuntu5) ) #1 SMP Tue Oct 2 15:34:46 PDT 2012
CPU: model name : AMD A6-3500 APU with Radeon(tm) HD Graphics
If you need any other system variables please let me know and I can
get those as well.
Upon shutdown or restart (from either the hard button on the case or
a "sudo shutdown -r now" the system crashes and does not actually
shut down. I can ssh in to the system and a dmesg shows the
following:
There should be a line like:
BUG: Dentry ... still in use (%d) [unmount of %s %s]
just before the oops. Can you please post that one as well? Also I see that
you are using nvidia module which taints the kernel. Can you try
reproducing the issue without the module loaded?
Honza
Here is the full output with no nvidia module. I also have the full
dmeg from start to finish if you would like it.
Thank you!
[ 237.186167] BUG: Dentry 880118772540{i=6e,n=info} still in use
(1) [unmount of rpc_pipefs rpc_pipefs]
[ 237.186179] [ cut here ]
[ 237.186181] kernel BUG at fs/dcache.c:967!
[ 237.186182] invalid opcode: [#1] SMP
[ 237.186185] Modules linked in: nls_utf8 udf crc_itu_t nfsv4
binfmt_misc nfsd nfs_acl auth_rpcgss nfs fscache lockd sunrpc
snd_hda_codec_hdmi snd_hda_codec_realtek xfs snd_hda_intel snd_hda_codec
snd_seq_midi snd_hwdep snd_rawmidi snd_pcm psmouse snd_seq_midi_event
rc_imon_mce serio_raw snd_seq imon rc_core snd_timer snd_seq_device snd
soundcore snd_page_alloc f71882fg r8169 ahci libahci
[ 237.186203] CPU 2
[ 237.186206] Pid: 3063, comm: umount Not tainted 3.6.0 #1 System
manufacturer System Product Name/F1A55-M LX PLUS
[ 237.186208] RIP: 0010:[] []
shrink_dcache_for_umount_subtree+0x1e6/0x1f0
[ 237.186214] RSP: 0018:8801181afd98 EFLAGS: 00010296
[ 237.186215] RAX: 005d RBX: 880118772540 RCX:
14bd
[ 237.186217] RDX: 3256 RSI: 0046 RDI:
81bbf9bc
[ 237.186218] RBP: 8801181afdb8 R08: 000a R09:
[ 237.186219] R10: 0383 R11: 0382 R12:
88011873b9c0
[ 237.186220] R13: 8801177a2b80 R14: 8801177a2bb0 R15:
88011287d800
[ 237.186222] FS: 7f67049b1800() GS:88011ed0()
knlGS:
[ 237.186223] CS: 0010 DS: ES: CR0: 8005003b
[ 237.186225] CR2: 7f3e1de8 CR3: 000118a18000 CR4:
07e0
[ 237.186226] DR0: DR1: DR2:
[ 237.186227] DR3: DR6: 0ff0 DR7:
0400
[ 237.186229] Process umount (pid: 3063, threadinfo 8801181ae000,
task 880110fbc440)
[ 237.186230] Stack:
[ 237.186231] 88011287db50 88011873b780 88011287d800
a021d3c0
[ 237.186233] 8801181afdd8 8116de93 0001
88011287d800
[ 237.186235] 8801181afe08 811583bc 88011873b820
0015
[ 237.186238] Call Trace:
[ 237.186241] [] shrink_dcache_for_umount+0x33/0x60
[ 237.186244] [] generic_shutdown_super+0x2c/0xf0
[ 237.186247] [] kill_anon_super+0x16/0x30
[ 237.186249] [] kill_litter_super+0x27/0x30
[ 237.186265] [] rpc_kill_sb+0x99/0xc0 [sunrpc]
[ 237.186268] [] deactivate_locked_super+0x3c/0xa0
[ 237.186270] [] deactivate_super+0x4e/0x70
[ 237.186273] [] mntput_no_expire+0x106/0x160
[ 237.186276] [] sys_umount+0x6e/0x3b0
[ 237.186279] [] system_call_fastpath+0x1a/0x1f
[ 237.186280] Code: 00 00 48 8b 40 28 4c 8b 08 48 8b 43 30 48 85 c0 74
04 48 8b 50 40 48 89 34 24 48 c7 c7 48 69 7c 81 48 89 de 31 c0 e8 09 62
40 00 <0f> 0b 0f 0b 66 0f 1f 44 00 00 55 48 89 e5 41 54 53 66 66 66 66
[ 237.186301] RIP []
shrink_dcache_for_umount_subtree+0x1e6/0x1f0
[ 237.186303] RSP
[ 237.186320] ---[ end trace 74629a120592ec3c ]---
[ 238.707925] mtrr: no MTRR for f900,e0 found
[ 245.162939] imon:send_packet: task interrupted
[ 245.218338] nfsd: last server has exited, flushing export cache
--
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Please read the FAQ at http://www.tux.org/lkml/
PROBLEM: 3.6.0 kernel BUG at fs/dcache.c:967 during shutdown / restart
I've not submitted a kernel bug before but I've read the bug reporting pages. I'll try to do my best and if you need more information please let me know. Please feel free to cc me on the answer or if you have questions. I'm using Linux Mint 13 (64 bit) on AMD hardware with a self compiled 3.6.0 kernel for my MythTV HTPC. Kernel version: Linux version 3.6.0 (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #1 SMP Tue Oct 2 15:34:46 PDT 2012 CPU: model name : AMD A6-3500 APU with Radeon(tm) HD Graphics If you need any other system variables please let me know and I can get those as well. Upon shutdown or restart (from either the hard button on the case or a "sudo shutdown -r now" the system crashes and does not actually shut down. I can ssh in to the system and a dmesg shows the following: [102792.710563] [ cut here ] [102792.710564] kernel BUG at fs/dcache.c:967! [102792.710566] invalid opcode: [#1] SMP [102792.710568] Modules linked in: nls_utf8 udf crc_itu_t nfsv4 binfmt_misc nfsd nfs_acl auth_rpcgss nfs fscache lockd sunrpc snd_hda_codec_hdmi xfs nvidia(PO) rc_imon_mce imon rc_core snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_seq_midi snd_hwdep snd_rawmidi snd_pcm psmouse snd_seq_midi_event snd_seq serio_raw snd_seq_device snd_timer snd soundcore snd_page_alloc f71882fg r8169 ahci libahci [102792.710587] CPU 0 [102792.710590] Pid: 29771, comm: umount Tainted: P O 3.6.0 #1 System manufacturer System Product Name/F1A55-M LX PLUS [102792.710592] RIP: 0010:[] [] shrink_dcache_for_umount_subtree+0x1e6/0x1f0 [102792.710598] RSP: 0018:880118f6dd98 EFLAGS: 00010296 [102792.710600] RAX: 005d RBX: 88011092acc0 RCX: 13ae [102792.710601] RDX: 4663 RSI: 0046 RDI: 81bbf9bc [102792.710602] RBP: 880118f6ddb8 R08: 000a R09: [102792.710604] R10: 039a R11: 0399 R12: 880110a5c900 [102792.710605] R13: 880118fa9d00 R14: 880118fa9d30 R15: 8801180c9000 [102792.710607] FS: 7f9cc4c16800() GS:88011ec0() knlGS: [102792.710608] CS: 0010 DS: ES: CR0: 80050033 [102792.710609] CR2: 7f9cc4241120 CR3: 000117993000 CR4: 07f0 [102792.710611] DR0: DR1: DR2: [102792.710612] DR3: DR6: 0ff0 DR7: 0400 [102792.710614] Process umount (pid: 29771, threadinfo 880118f6c000, task 88007b8edb00) [102792.710614] Stack: [102792.710616] 8801180c9350 880110a5c6c0 8801180c9000 a0d0f3c0 [102792.710618] 880118f6ddd8 8116de93 0001 8801180c9000 [102792.710620] 880118f6de08 811583bc 880110a5c760 0014 [102792.710622] Call Trace: [102792.710626] [] shrink_dcache_for_umount+0x33/0x60 [102792.710629] [] generic_shutdown_super+0x2c/0xf0 [102792.710632] [] kill_anon_super+0x16/0x30 [102792.710634] [] kill_litter_super+0x27/0x30 [102792.710650] [] rpc_kill_sb+0x99/0xc0 [sunrpc] [102792.710653] [] deactivate_locked_super+0x3c/0xa0 [102792.710655] [] deactivate_super+0x4e/0x70 [102792.710658] [] mntput_no_expire+0x106/0x160 [102792.710661] [] sys_umount+0x6e/0x3b0 [102792.710664] [] system_call_fastpath+0x1a/0x1f [102792.710665] Code: 00 00 48 8b 40 28 4c 8b 08 48 8b 43 30 48 85 c0 74 04 48 8b 50 40 48 89 34 24 48 c7 c7 48 69 7c 81 48 89 de 31 c0 e8 09 62 40 00 <0f> 0b 0f 0b 66 0f 1f 44 00 00 55 48 89 e5 41 54 53 66 66 66 66 [102792.710686] RIP [] shrink_dcache_for_umount_subtree+0x1e6/0x1f0 [102792.710689] RSP [102792.710705] ---[ end trace 6cebf99f8c65907b ]--- Thank you, Neil -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
