Hello,
Got given a Prodif Plus (SekD/Marian) card and started trying to get it to
work... but it isn't plain sailing. ;-)
I'm using a Debian copy of the Linux 2.6.15 source code, and ALSA drivers
1.0.11rc2 downloaded from alsa-project.org. (I think 2.6.15 actually comes
with ALSA 1.0.10rc3, but that fails to compile on my box.) Also, I'm running
the latest Debian alsa-utils package (1.0.10-1), but that doesn't seem to be
relevant to the problems I'm getting.
First problem I hit (and have a fix/workaround for), is that the VENDOR_NAME
and MODULE_DESCRIPTION in pdplus.c contain the slash '/' character:
#define VENDOR_NAME "SekD/Marian"
[...]
MODULE_DESCRIPTION("SekD/Marian Prodif Plus");
This causes the module to fail to register (error 13, permission denied) in
sysfs as you can't create a directory entry containing a slash character. If
I'm right about this, then I'm more than willing to submit a patch. Any
preferences as to what to replace the slash with?
So, I've removed the slash for the time being. I've also gone and replaced
spaces in the "FULL_NAME" to underscores.
Now, things get a fair bit further: the card seems to get registered OK, but
then all of a sudden the module gets unregistered and oops start flying left,
right and centre.
Here's a shortened version of the kernel output (kernel compiled with kobject
debug enabled) - the full version is available in the attached file:
kobject_hotplug: module seq=906 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/module/snd_pdplus SUBSYSTEM=module
pdplus: version 0.0.5
kobject_hotplug: drivers seq=907 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/bus/pci/drivers/SekD_ProdifPlus SUBSYSTEM=drivers
Generating PCM devices.
Generating mixer.
Generating /proc entry.
Uploading circuit.
jiffies=-175567
pdplus: DCO clock needed 1 loops to stabilise (freq=44097 Hz)
jiffies=-175385
Finishing registration.
kobject_hotplug: sound seq=908 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0 SUBSYSTEM=sound
[...]
kobject_hotplug: sound seq=916 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/mixer SUBSYSTEM=sound
kobject snd_pdplus: unregistering
kobject_hotplug: module seq=917 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=remove DEVPATH=/module/snd_pdplus SUBSYSTEM=module
Unable to handle kernel paging request at virtual address e0c02854
[...]
Process udevd (pid: 5218, threadinfo=d595c000 task=df3ffab0)
[...]
Call Trace:
[<c01a3cce>] kobject_get+0x12/0x17
[<c017a55e>] sysfs_getlink+0x54/0xb0
[<c017a5df>] sysfs_follow_link+0x25/0x3b
[<c0155485>] generic_readlink+0x23/0x6e
[<c0119a23>] current_fs_time+0x3e/0x58
[<c014f353>] sys_readlink+0x73/0x91
[<c0102a6d>] syscall_call+0x7/0xb
Any ideas/pointers/solutions ;-) please?
Thanks,
Eric Mountain
ll_kobj_path: path = '/class/vc/vcsa3'
kobject_hotplug: vc seq=899 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcsa3 SUBSYSTEM=vc
kobject vcs6: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcs6
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcs6
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcs6'
kobject_hotplug: vc seq=900 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcs6 SUBSYSTEM=vc
kobject vcsa6: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcsa6
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcsa6
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcsa6'
kobject_hotplug: vc seq=901 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcsa6 SUBSYSTEM=vc
kobject vcs5: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcs5
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcs5
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcs5'
kobject_hotplug: vc seq=902 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcs5 SUBSYSTEM=vc
kobject vcsa5: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcsa5
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcsa5
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcsa5'
kobject_hotplug: vc seq=903 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcsa5 SUBSYSTEM=vc
kobject vcs4: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcs4
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcs4
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcs4'
kobject_hotplug: vc seq=904 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcs4 SUBSYSTEM=vc
kobject vcsa4: registering. parent: vc, set: class_obj
calling create_dir in kobject_add for vcsa4
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for vcsa4
kobject_hotplug
fill_kobj_path: path = '/class/vc/vcsa4'
kobject_hotplug: vc seq=905 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/vc/vcsa4 SUBSYSTEM=vc
kobject snd_pdplus: registering. parent: <NULL>, set: module
calling create_dir in kobject_add for snd_pdplus
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for snd_pdplus
kobject_hotplug
fill_kobj_path: path = '/module/snd_pdplus'
kobject_hotplug: module seq=906 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/module/snd_pdplus SUBSYSTEM=module
pdplus: version 0.0.5
kobject SekD_ProdifPlus: registering. parent: <NULL>, set: drivers
calling create_dir in kobject_add for SekD_ProdifPlus
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for SekD_ProdifPlus
kobject_hotplug
fill_kobj_path: path = '/bus/pci/drivers/SekD_ProdifPlus'
kobject_hotplug: drivers seq=907 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/bus/pci/drivers/SekD_ProdifPlus SUBSYSTEM=drivers
base=0xe6020000, offs=0x0, remapped=0xe0bc6000
base=0xe6000000, offs=0x0, remapped=0xe0c40000
base=0xe6022000, offs=0x0, remapped=0xe0bd8000
base=0xe6023000, offs=0x0, remapped=0xe0bda000
Generating PCM devices.
Generating mixer.
Generating /proc entry.
Uploading circuit.
jiffies=-175567
pdplus: DCO clock needed 1 loops to stabilise (freq=44097 Hz)
jiffies=-175385
Finishing registration.
kobject controlC0: registering. parent: sound, set: class_obj
calling create_dir in kobject_add for controlC0
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for controlC0
kobject_hotplug
fill_kobj_path: path = '/class/sound/controlC0'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=908 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0 SUBSYSTEM=sound
kobject pcmC0D0p: registering. parent: controlC0, set: class_obj
calling create_dir in kobject_add for pcmC0D0p
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for pcmC0D0p
kobject_hotplug
fill_kobj_path: path = '/class/sound/controlC0/pcmC0D0p'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=909 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0/pcmC0D0p SUBSYSTEM=sound
kobject pcmC0D0c: registering. parent: controlC0, set: class_obj
calling create_dir in kobject_add for pcmC0D0c
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for pcmC0D0c
kobject_hotplug
fill_kobj_path: path = '/class/sound/controlC0/pcmC0D0c'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=910 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0/pcmC0D0c SUBSYSTEM=sound
kobject dsp: registering. parent: sound, set: class_obj
calling create_dir in kobject_add for dsp
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for dsp
kobject_hotplug
fill_kobj_path: path = '/class/sound/dsp'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=911 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/dsp SUBSYSTEM=sound
kobject audio: registering. parent: sound, set: class_obj
calling create_dir in kobject_add for audio
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for audio
kobject_hotplug
fill_kobj_path: path = '/class/sound/audio'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=912 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/audio SUBSYSTEM=sound
kobject pcmC0D1p: registering. parent: controlC0, set: class_obj
calling create_dir in kobject_add for pcmC0D1p
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for pcmC0D1p
kobject_hotplug
fill_kobj_path: path = '/class/sound/controlC0/pcmC0D1p'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=913 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0/pcmC0D1p SUBSYSTEM=sound
kobject pcmC0D1c: registering. parent: controlC0, set: class_obj
calling create_dir in kobject_add for pcmC0D1c
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for pcmC0D1c
kobject_hotplug
fill_kobj_path: path = '/class/sound/controlC0/pcmC0D1c'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=914 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/controlC0/pcmC0D1c SUBSYSTEM=sound
kobject adsp: registering. parent: sound, set: class_obj
calling create_dir in kobject_add for adsp
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for adsp
kobject_hotplug
fill_kobj_path: path = '/class/sound/adsp'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=915 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/adsp SUBSYSTEM=sound
kobject mixer: registering. parent: sound, set: class_obj
calling create_dir in kobject_add for mixer
sysfs_create_dir returned 0
sysfs_populate_dir returned 0
create_dir returned 0 for mixer
kobject_hotplug
fill_kobj_path: path = '/class/sound/mixer'
fill_kobj_path: path = '/devices/pci0000:00/0000:00:09.0'
kobject_hotplug: sound seq=916 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=add DEVPATH=/class/sound/mixer SUBSYSTEM=sound
kobject snd_pdplus: unregistering
[<c01a3ca1>] kobject_unregister+0x16/0x31
[<c01291c5>] free_module+0x19/0x60
[<c012a2dd>] sys_init_module+0xfc/0x164
[<c0102a6d>] syscall_call+0x7/0xb
kobject_hotplug
fill_kobj_path: path = '/module/snd_pdplus'
kobject_hotplug: module seq=917 HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin
ACTION=remove DEVPATH=/module/snd_pdplus SUBSYSTEM=module
Unable to handle kernel paging request at virtual address e0c02854
printing eip:
c01a44e4
*pde = 1e317067
*pte = 00000000
Oops: 0000 [#1]
Modules linked in: ipv6 sch_ingress cls_u32 sch_sfq sch_cbq ipt_MASQUERADE
ipt_owner ipt_REDIRECT iptable_nat ip_nat iptable_mangle ipt_REJECT ipt_LOG
ipt_state ip_conntrack nfnetlink iptable_filter iptable_raw ip_tables
binfmt_misc reiserfs nls_iso8859_1 nls_cp437 vfat fat dm_mod snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_pcm snd_timer
snd_page_alloc snd_mixer_oss snd soundcore tcp_diag inet_diag esp4 ah4 tun
autofs4 loop lp uhci_hcd via686a usbcore i2c_isa shpchp 8139too mii i2c_core
pci_hotplug amd_k7_agp agpgart psmouse parport_pc parport serio_raw ide_cd
cdrom ext3 jbd mbcache ide_disk generic ide_generic via82cxxx ide_core evdev
mousedev
CPU: 0
EIP: 0060:[<c01a44e4>] Not tainted VLI
EFLAGS: 00010286 (2.6.15e)
EIP is at kref_get+0x5/0x2d
eax: e0c02854 ebx: e0c02854 ecx: c12b30e0 edx: d5987000
esi: d595df00 edi: df94e8ac ebp: d595df00 esp: d595deb8
ds: 007b es: 007b ss: 0068
Process udevd (pid: 5218, threadinfo=d595c000 task=df3ffab0)
Stack: e0c0283c c01a3cce e0c02854 d5ffadd8 c017a55e e0c0283c d5987000 d595df00
00000100 d595df00 c017a5df d5ffadd8 d5987000 00000000 d5ffadd8 c0155485
d5ffadd8 d595df00 d58ba1ff 00000000 00000001 d5fc22d4 1c1f15c8 43d9422c
Call Trace:
[<c01a3cce>] kobject_get+0x12/0x17
[<c017a55e>] sysfs_getlink+0x54/0xb0
[<c017a5df>] sysfs_follow_link+0x25/0x3b
[<c0155485>] generic_readlink+0x23/0x6e
[<c0119a23>] current_fs_time+0x3e/0x58
[<c014f353>] sys_readlink+0x73/0x91
[<c0102a6d>] syscall_call+0x7/0xb
Code: 83 c4 10 39 eb 89 1e 7f 06 ff 07 31 c0 eb 05 b8 f4 ff ff ff 5b 5b 5e 5f
5d c3 90 8b 44 24 04 c7 00 01 00 00 00 c3 53 8b 5c 24 08 <8b> 03 85 c0 75 1e 6a
20 68 4f 07 28 c0 68 8c aa 26 c0 68 c4 2e
<1>Unable to handle kernel paging request at virtual address e0c02854
printing eip:
c01a44e4
*pde = 1e317067
*pte = 00000000
Oops: 0000 [#2]
Modules linked in: ipv6 sch_ingress cls_u32 sch_sfq sch_cbq ipt_MASQUERADE
ipt_owner ipt_REDIRECT iptable_nat ip_nat iptable_mangle ipt_REJECT ipt_LOG
ipt_state ip_conntrack nfnetlink iptable_filter iptable_raw ip_tables
binfmt_misc reiserfs nls_iso8859_1 nls_cp437 vfat fat dm_mod snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_pcm snd_timer
snd_page_alloc snd_mixer_oss snd soundcore tcp_diag inet_diag esp4 ah4 tun
autofs4 loop lp uhci_hcd via686a usbcore i2c_isa shpchp 8139too mii i2c_core
pci_hotplug amd_k7_agp agpgart psmouse parport_pc parport serio_raw ide_cd
cdrom ext3 jbd mbcache ide_disk generic ide_generic via82cxxx ide_core evdev
mousedev
CPU: 0
EIP: 0060:[<c01a44e4>] Not tainted VLI
EFLAGS: 00010286 (2.6.15e)
EIP is at kref_get+0x5/0x2d
eax: e0c02854 ebx: e0c02854 ecx: c12b3300 edx: d5998000
esi: d595bf00 edi: df94e8ac ebp: d595bf00 esp: d595beb8
ds: 007b es: 007b ss: 0068
Process udevd (pid: 5219, threadinfo=d595a000 task=d9712570)
Stack: e0c0283c c01a3cce e0c02854 d5ffadd8 c017a55e e0c0283c d5998000 d595bf00
00000100 d595bf00 c017a5df d5ffadd8 d5998000 00000000 d5ffadd8 c0155485
d5ffadd8 d595bf00 c026a1ff 00000000 00000001 d5fc22d4 1cb7a658 43d9422c
Call Trace:
[<c01a3cce>] kobject_get+0x12/0x17
[<c017a55e>] sysfs_getlink+0x54/0xb0
[<c017a5df>] sysfs_follow_link+0x25/0x3b
[<c0155485>] generic_readlink+0x23/0x6e
[<c0119a23>] current_fs_time+0x3e/0x58
[<c014f353>] sys_readlink+0x73/0x91
[<c0102a6d>] syscall_call+0x7/0xb
Code: 83 c4 10 39 eb 89 1e 7f 06 ff 07 31 c0 eb 05 b8 f4 ff ff ff 5b 5b 5e 5f
5d c3 90 8b 44 24 04 c7 00 01 00 00 00 c3 53 8b 5c 24 08 <8b> 03 85 c0 75 1e 6a
20 68 4f 07 28 c0 68 8c aa 26 c0 68 c4 2e
<1>Unable to handle kernel paging request at virtual address e0c02854
printing eip:
c01a44e4
*pde = 1e317067
*pte = 00000000
Oops: 0000 [#3]
Modules linked in: ipv6 sch_ingress cls_u32 sch_sfq sch_cbq ipt_MASQUERADE
ipt_owner ipt_REDIRECT iptable_nat ip_nat iptable_mangle ipt_REJECT ipt_LOG
ipt_state ip_conntrack nfnetlink iptable_filter iptable_raw ip_tables
binfmt_misc reiserfs nls_iso8859_1 nls_cp437 vfat fat dm_mod snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_pcm snd_timer
snd_page_alloc snd_mixer_oss snd soundcore tcp_diag inet_diag esp4 ah4 tun
autofs4 loop lp uhci_hcd via686a usbcore i2c_isa shpchp 8139too mii i2c_core
pci_hotplug amd_k7_agp agpgart psmouse parport_pc parport serio_raw ide_cd
cdrom ext3 jbd mbcache ide_disk generic ide_generic via82cxxx ide_core evdev
mousedev
CPU: 0
EIP: 0060:[<c01a44e4>] Not tainted VLI
EFLAGS: 00010286 (2.6.15e)
EIP is at kref_get+0x5/0x2d
eax: e0c02854 ebx: e0c02854 ecx: c12b3200 edx: d5990000
esi: d658df00 edi: df94e8ac ebp: d658df00 esp: d658deb8
ds: 007b es: 007b ss: 0068
Process udevd (pid: 5220, threadinfo=d658c000 task=d66a0590)
Stack: e0c0283c c01a3cce e0c02854 d5ffadd8 c017a55e e0c0283c d5990000 d658df00
00000100 d658df00 c017a5df d5ffadd8 d5990000 00000000 d5ffadd8 c0155485
d5ffadd8 d658df00 d6dea1ff 00000000 00000001 d5fc22d4 1d31b398 43d9422c
Call Trace:
[<c01a3cce>] kobject_get+0x12/0x17
[<c017a55e>] sysfs_getlink+0x54/0xb0
[<c017a5df>] sysfs_follow_link+0x25/0x3b
[<c0155485>] generic_readlink+0x23/0x6e
[<c0119a23>] current_fs_time+0x3e/0x58
[<c014f353>] sys_readlink+0x73/0x91
[<c0102a6d>] syscall_call+0x7/0xb
Code: 83 c4 10 39 eb 89 1e 7f 06 ff 07 31 c0 eb 05 b8 f4 ff ff ff 5b 5b 5e 5f
5d c3 90 8b 44 24 04 c7 00 01 00 00 00 c3 53 8b 5c 24 08 <8b> 03 85 c0 75 1e 6a
20 68 4f 07 28 c0 68 8c aa 26 c0 68 c4 2e
<1>Unable to handle kernel paging request at virtual address e0c02854
printing eip:
c01a44e4
*pde = 1e317067
*pte = 00000000
Oops: 0000 [#4]
Modules linked in: ipv6 sch_ingress cls_u32 sch_sfq sch_cbq ipt_MASQUERADE
ipt_owner ipt_REDIRECT iptable_nat ip_nat iptable_mangle ipt_REJECT ipt_LOG
ipt_state ip_conntrack nfnetlink iptable_filter iptable_raw ip_tables
binfmt_misc reiserfs nls_iso8859_1 nls_cp437 vfat fat dm_mod snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_pcm snd_timer
snd_page_alloc snd_mixer_oss snd soundcore tcp_diag inet_diag esp4 ah4 tun
autofs4 loop lp uhci_hcd via686a usbcore i2c_isa shpchp 8139too mii i2c_core
pci_hotplug amd_k7_agp agpgart psmouse parport_pc parport serio_raw ide_cd
cdrom ext3 jbd mbcache ide_disk generic ide_generic via82cxxx ide_core evdev
mousedev
CPU: 0
EIP: 0060:[<c01a44e4>] Not tainted VLI
EFLAGS: 00010286 (2.6.15e)
EIP is at kref_get+0x5/0x2d
eax: e0c02854 ebx: e0c02854 ecx: c12b0a00 edx: d5850000
esi: d595df00 edi: df94e8ac ebp: d595df00 esp: d595deb8
ds: 007b es: 007b ss: 0068
Process udevd (pid: 5221, threadinfo=d595c000 task=df3ffab0)
Stack: e0c0283c c01a3cce e0c02854 d5ffadd8 c017a55e e0c0283c d5850000 d595df00
00000100 d595df00 c017a5df d5ffadd8 d5850000 00000000 d5ffadd8 c0155485
d5ffadd8 d595df00 c026a1ff 00000000 00000001 d5fc22d4 1dabc0d8 43d9422c
Call Trace:
[<c01a3cce>] kobject_get+0x12/0x17
[<c017a55e>] sysfs_getlink+0x54/0xb0
[<c017a5df>] sysfs_follow_link+0x25/0x3b
[<c0155485>] generic_readlink+0x23/0x6e
[<c0119a23>] current_fs_time+0x3e/0x58
[<c014f353>] sys_readlink+0x73/0x91
[<c0102a6d>] syscall_call+0x7/0xb
Code: 83 c4 10 39 eb 89 1e 7f 06 ff 07 31 c0 eb 05 b8 f4 ff ff ff 5b 5b 5e 5f
5d c3 90 8b 44 24 04 c7 00 01 00 00 00 c3 53 8b 5c 24 08 <8b> 03 85 c0 75 1e 6a
20 68 4f 07 28 c0 68 8c aa 26 c0 68 c4 2e
