Re: regression (bisected): "modprobe parport_pc" hangs in current mainline

[Michal Kubecek]

On Sun, Mar 17, 2019 at 05:01:37PM +0000, Sudip Mukherjee wrote:
> On Wed, Mar 13, 2019 at 6:45 AM Michal Kubecek <mkubecek@xxxxxxx> wrote:
> > I encountered a regression in current (post-5.0) mainline kernel which I
> > bisected to commit 1aec4211204d ("parport: daisy: use new parport device
> > model"). Running "modprobe parport_pc" hangs up:
> 
> Can you please send me your .config so that I can test it from my side.

Attaching two versions: config-full.gz is the real life config from the
machine where I found the issue and config-mini.gz is a minimized config
I was using while bisecting the issue. (I made a mistake and thought
that I have seen the issue with snapshot before both parport commits so
that I ran a full bisect instead of simply checking the two parport
commits which came in the merge window.)

> > tweed:~ # ps ax | grep modprobe
> >  1206 pts/0    D+     0:00 modprobe parport_pc
> >  1209 ?        S      0:00 /sbin/modprobe -q -- parport_lowlevel
> >  1211 pts/1    S+     0:00 grep modprobe
> > tweed:~ # cat /proc/1206/stack
> > [<0>] call_usermodehelper_exec+0xc7/0x140
> > [<0>] __request_module+0x1a1/0x430
> > [<0>] __parport_register_driver+0x142/0x150 [parport]
> 
> And also, modprobe is trying to load a dependent module, so it will be
> great if you can also do a "lsmod" before doing the modprobe and I can
> check what is going wrong.

Attached are three lists:

  - lsmod-before ... before running "modprobe parport_pc"
  - lsmod-test   ... while "modprobe parport_pc" is stuck
  - lsmod-after  ... after killing second modprobe (1209 above)

Killing the second modprobe (PID 1209 above) lets the first finish and
as a result, parport, parport_pc and ppdev are loaded (it's the only
difference against lsmod-before). When modprobe is stuck, lsmod shows
parport with refcount of 1 (the only difference against lsmod-before).

Michal

Attachment: config-full.gz
Description: GNU Zip compressed data

Attachment: config-mini.gz
Description: GNU Zip compressed data

Module                  Size  Used by
authenc                16384  2
echainiv               16384  2
esp4                   24576  2
xfrm4_mode_transport    16384  4
tun                    57344  2
xt_REDIRECT            20480  3
ipt_MASQUERADE         20480  2
xt_nat                 16384  2
deflate                16384  0
iptable_nat            16384  1
twofish_generic        20480  0
nf_nat                 49152  4 ipt_MASQUERADE,xt_nat,iptable_nat,xt_REDIRECT
twofish_avx_x86_64     53248  0
twofish_x86_64_3way    28672  1 twofish_avx_x86_64
twofish_x86_64         16384  2 twofish_x86_64_3way,twofish_avx_x86_64
twofish_common         24576  4 twofish_x86_64,twofish_generic,twofish_x86_64_3way,twofish_avx_x86_64
camellia_generic       32768  0
af_packet              53248  10
nf_log_ipv4            16384  1
nf_log_common          16384  1 nf_log_ipv4
xt_LOG                 20480  1
camellia_aesni_avx_x86_64    28672  0
camellia_x86_64        53248  1 camellia_aesni_avx_x86_64
xt_conntrack           16384  2
nf_conntrack          155648  5 xt_conntrack,nf_nat,ipt_MASQUERADE,xt_nat,xt_REDIRECT
nf_defrag_ipv6         24576  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
serpent_avx_x86_64     49152  0
serpent_sse2_x86_64    53248  0
serpent_generic        28672  2 serpent_sse2_x86_64,serpent_avx_x86_64
blowfish_generic       16384  0
blowfish_x86_64        24576  0
blowfish_common        20480  2 blowfish_generic,blowfish_x86_64
cast5_avx_x86_64       49152  0
fuse                  131072  3
cast5_generic          24576  1 cast5_avx_x86_64
cast_common            16384  2 cast5_generic,cast5_avx_x86_64
des_generic            24576  0
cmac                   16384  0
ipt_REJECT             16384  21
nf_reject_ipv4         16384  1 ipt_REJECT
xcbc                   16384  0
rmd160                 20480  0
xt_tcpudp              20480  50
iptable_filter         16384  1
ip_tables              32768  2 iptable_filter,iptable_nat
x_tables               45056  9 xt_conntrack,iptable_filter,xt_LOG,xt_tcpudp,ipt_MASQUERADE,xt_nat,ipt_REJECT,ip_tables,xt_REDIRECT
sha512_ssse3           45056  0
sha512_generic         16384  1 sha512_ssse3
bpfilter               36864  0
af_key                 45056  2
xfrm_algo              16384  2 af_key,esp4
8021q                  40960  0
garp                   16384  1 8021q
mrp                    20480  1 8021q
stp                    16384  1 garp
llc                    16384  2 stp,garp
iscsi_ibft             16384  0
iscsi_boot_sysfs       16384  1 iscsi_ibft
it87                   65536  0
hwmon_vid              16384  1 it87
msr                    16384  0
joydev                 28672  0
hid_generic            16384  0
xfs                  1433600  3
libcrc32c              16384  3 nf_conntrack,nf_nat,xfs
edac_mce_amd           32768  0
kvm_amd               110592  0
ccp                    98304  1 kvm_amd
kvm                   733184  1 kvm_amd
irqbypass              16384  1 kvm
snd_seq_dummy          16384  0
snd_seq_oss            49152  0
snd_emu10k1_synth      20480  0
snd_emux_synth         53248  1 snd_emu10k1_synth
snd_seq_midi_emul      20480  1 snd_emux_synth
snd_seq_virmidi        16384  1 snd_emux_synth
snd_seq_midi           20480  0
snd_seq_midi_event     16384  3 snd_seq_midi,snd_seq_oss,snd_seq_virmidi
raid1                  49152  3
md_mod                167936  3 raid1
crct10dif_pclmul       16384  1
crc32_pclmul           16384  0
ghash_clmulni_intel    16384  0
snd_emu10k1           192512  3 snd_emu10k1_synth
snd_util_mem           16384  2 snd_emu10k1,snd_emux_synth
snd_ac97_codec        147456  1 snd_emu10k1
ac97_bus               16384  1 snd_ac97_codec
snd_hwdep              16384  2 snd_emu10k1,snd_emux_synth
snd_rawmidi            45056  3 snd_seq_midi,snd_emu10k1,snd_seq_virmidi
usbhid                 65536  2
snd_pcm               143360  2 snd_emu10k1,snd_ac97_codec
snd_seq                86016  9 snd_seq_midi,snd_seq_oss,snd_seq_midi_event,snd_seq_virmidi,snd_seq_midi_emul,snd_emux_synth,snd_seq_dummy
aesni_intel           372736  5
snd_seq_device         16384  7 snd_seq,snd_seq_midi,snd_seq_oss,snd_emu10k1,snd_emu10k1_synth,snd_emux_synth,snd_rawmidi
snd_timer              40960  3 snd_seq,snd_emu10k1,snd_pcm
aes_x86_64             20480  1 aesni_intel
crypto_simd            16384  6 camellia_aesni_avx_x86_64,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,cast5_avx_x86_64,twofish_avx_x86_64
cryptd                 28672  5 crypto_simd,ghash_clmulni_intel,aesni_intel
glue_helper            16384  7 camellia_aesni_avx_x86_64,camellia_x86_64,twofish_x86_64_3way,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,twofish_avx_x86_64
8139too                45056  0
snd                   102400  15 snd_seq,snd_seq_device,snd_hwdep,snd_seq_oss,snd_emu10k1,snd_timer,snd_ac97_codec,snd_seq_virmidi,snd_emux_synth,snd_pcm,snd_rawmidi
mxm_wmi                16384  0
pcspkr                 16384  0
k10temp                16384  0
fam15h_power           16384  0
sp5100_tco             20480  0
soundcore              16384  1 snd
8139cp                 36864  0
emu10k1_gp             16384  0
gameport               16384  2 emu10k1_gp
mii                    16384  2 8139cp,8139too
r8169                  94208  0
i2c_piix4              28672  0
radeon               1642496  73
realtek                20480  1
ttm                   114688  1 radeon
libphy                 90112  2 r8169,realtek
drm_kms_helper        212992  1 radeon
button                 20480  0
drm                   487424  14 drm_kms_helper,radeon,ttm
fb_sys_fops            16384  1 drm_kms_helper
syscopyarea            16384  1 drm_kms_helper
sysfillrect            16384  1 drm_kms_helper
sysimgblt              16384  1 drm_kms_helper
i2c_algo_bit           16384  1 radeon
pcc_cpufreq            20480  0
acpi_cpufreq           28672  0
ohci_pci               20480  0
crc32c_intel           24576  5
firewire_ohci          45056  0
firewire_core          77824  1 firewire_ohci
crc_itu_t              16384  1 firewire_core
ehci_pci               20480  0
ohci_hcd               57344  1 ohci_pci
sr_mod                 28672  0
ehci_hcd               98304  1 ehci_pci
cdrom                  73728  1 sr_mod
xhci_pci               20480  0
xhci_hcd              262144  1 xhci_pci
usbcore               303104  9 xhci_hcd,ohci_hcd,ehci_pci,usbhid,ehci_hcd,xhci_pci,ohci_pci
wmi                    32768  1 mxm_wmi
sg                     40960  0
dm_multipath           36864  0
dm_mod                155648  9 dm_multipath
scsi_dh_rdac           16384  0
scsi_dh_emc            16384  0
scsi_dh_alua           20480  0
Module                  Size  Used by
parport                61440  1
authenc                16384  2
echainiv               16384  2
esp4                   24576  2
xfrm4_mode_transport    16384  4
tun                    57344  2
xt_REDIRECT            20480  3
ipt_MASQUERADE         20480  2
xt_nat                 16384  2
deflate                16384  0
iptable_nat            16384  1
twofish_generic        20480  0
nf_nat                 49152  4 ipt_MASQUERADE,xt_nat,iptable_nat,xt_REDIRECT
twofish_avx_x86_64     53248  0
twofish_x86_64_3way    28672  1 twofish_avx_x86_64
twofish_x86_64         16384  2 twofish_x86_64_3way,twofish_avx_x86_64
twofish_common         24576  4 twofish_x86_64,twofish_generic,twofish_x86_64_3way,twofish_avx_x86_64
camellia_generic       32768  0
af_packet              53248  10
nf_log_ipv4            16384  1
nf_log_common          16384  1 nf_log_ipv4
xt_LOG                 20480  1
camellia_aesni_avx_x86_64    28672  0
camellia_x86_64        53248  1 camellia_aesni_avx_x86_64
xt_conntrack           16384  2
nf_conntrack          155648  5 xt_conntrack,nf_nat,ipt_MASQUERADE,xt_nat,xt_REDIRECT
nf_defrag_ipv6         24576  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
serpent_avx_x86_64     49152  0
serpent_sse2_x86_64    53248  0
serpent_generic        28672  2 serpent_sse2_x86_64,serpent_avx_x86_64
blowfish_generic       16384  0
blowfish_x86_64        24576  0
blowfish_common        20480  2 blowfish_generic,blowfish_x86_64
cast5_avx_x86_64       49152  0
fuse                  131072  3
cast5_generic          24576  1 cast5_avx_x86_64
cast_common            16384  2 cast5_generic,cast5_avx_x86_64
des_generic            24576  0
cmac                   16384  0
ipt_REJECT             16384  21
nf_reject_ipv4         16384  1 ipt_REJECT
xcbc                   16384  0
rmd160                 20480  0
xt_tcpudp              20480  50
iptable_filter         16384  1
ip_tables              32768  2 iptable_filter,iptable_nat
x_tables               45056  9 xt_conntrack,iptable_filter,xt_LOG,xt_tcpudp,ipt_MASQUERADE,xt_nat,ipt_REJECT,ip_tables,xt_REDIRECT
sha512_ssse3           45056  0
sha512_generic         16384  1 sha512_ssse3
bpfilter               36864  0
af_key                 45056  2
xfrm_algo              16384  2 af_key,esp4
8021q                  40960  0
garp                   16384  1 8021q
mrp                    20480  1 8021q
stp                    16384  1 garp
llc                    16384  2 stp,garp
iscsi_ibft             16384  0
iscsi_boot_sysfs       16384  1 iscsi_ibft
it87                   65536  0
hwmon_vid              16384  1 it87
msr                    16384  0
joydev                 28672  0
hid_generic            16384  0
xfs                  1433600  3
libcrc32c              16384  3 nf_conntrack,nf_nat,xfs
edac_mce_amd           32768  0
kvm_amd               110592  0
ccp                    98304  1 kvm_amd
kvm                   733184  1 kvm_amd
irqbypass              16384  1 kvm
snd_seq_dummy          16384  0
snd_seq_oss            49152  0
snd_emu10k1_synth      20480  0
snd_emux_synth         53248  1 snd_emu10k1_synth
snd_seq_midi_emul      20480  1 snd_emux_synth
snd_seq_virmidi        16384  1 snd_emux_synth
snd_seq_midi           20480  0
snd_seq_midi_event     16384  3 snd_seq_midi,snd_seq_oss,snd_seq_virmidi
raid1                  49152  3
md_mod                167936  3 raid1
crct10dif_pclmul       16384  1
crc32_pclmul           16384  0
ghash_clmulni_intel    16384  0
snd_emu10k1           192512  3 snd_emu10k1_synth
snd_util_mem           16384  2 snd_emu10k1,snd_emux_synth
snd_ac97_codec        147456  1 snd_emu10k1
ac97_bus               16384  1 snd_ac97_codec
snd_hwdep              16384  2 snd_emu10k1,snd_emux_synth
snd_rawmidi            45056  3 snd_seq_midi,snd_emu10k1,snd_seq_virmidi
usbhid                 65536  2
snd_pcm               143360  2 snd_emu10k1,snd_ac97_codec
snd_seq                86016  9 snd_seq_midi,snd_seq_oss,snd_seq_midi_event,snd_seq_virmidi,snd_seq_midi_emul,snd_emux_synth,snd_seq_dummy
aesni_intel           372736  5
snd_seq_device         16384  7 snd_seq,snd_seq_midi,snd_seq_oss,snd_emu10k1,snd_emu10k1_synth,snd_emux_synth,snd_rawmidi
snd_timer              40960  3 snd_seq,snd_emu10k1,snd_pcm
aes_x86_64             20480  1 aesni_intel
crypto_simd            16384  6 camellia_aesni_avx_x86_64,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,cast5_avx_x86_64,twofish_avx_x86_64
cryptd                 28672  5 crypto_simd,ghash_clmulni_intel,aesni_intel
glue_helper            16384  7 camellia_aesni_avx_x86_64,camellia_x86_64,twofish_x86_64_3way,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,twofish_avx_x86_64
8139too                45056  0
snd                   102400  15 snd_seq,snd_seq_device,snd_hwdep,snd_seq_oss,snd_emu10k1,snd_timer,snd_ac97_codec,snd_seq_virmidi,snd_emux_synth,snd_pcm,snd_rawmidi
mxm_wmi                16384  0
pcspkr                 16384  0
k10temp                16384  0
fam15h_power           16384  0
sp5100_tco             20480  0
soundcore              16384  1 snd
8139cp                 36864  0
emu10k1_gp             16384  0
gameport               16384  2 emu10k1_gp
mii                    16384  2 8139cp,8139too
r8169                  94208  0
i2c_piix4              28672  0
radeon               1642496  73
realtek                20480  1
ttm                   114688  1 radeon
libphy                 90112  2 r8169,realtek
drm_kms_helper        212992  1 radeon
button                 20480  0
drm                   487424  14 drm_kms_helper,radeon,ttm
fb_sys_fops            16384  1 drm_kms_helper
syscopyarea            16384  1 drm_kms_helper
sysfillrect            16384  1 drm_kms_helper
sysimgblt              16384  1 drm_kms_helper
i2c_algo_bit           16384  1 radeon
pcc_cpufreq            20480  0
acpi_cpufreq           28672  0
ohci_pci               20480  0
crc32c_intel           24576  5
firewire_ohci          45056  0
firewire_core          77824  1 firewire_ohci
crc_itu_t              16384  1 firewire_core
ehci_pci               20480  0
ohci_hcd               57344  1 ohci_pci
sr_mod                 28672  0
ehci_hcd               98304  1 ehci_pci
cdrom                  73728  1 sr_mod
xhci_pci               20480  0
xhci_hcd              262144  1 xhci_pci
usbcore               303104  9 xhci_hcd,ohci_hcd,ehci_pci,usbhid,ehci_hcd,xhci_pci,ohci_pci
wmi                    32768  1 mxm_wmi
sg                     40960  0
dm_multipath           36864  0
dm_mod                155648  9 dm_multipath
scsi_dh_rdac           16384  0
scsi_dh_emc            16384  0
scsi_dh_alua           20480  0
Module                  Size  Used by
ppdev                  24576  0
parport_pc             53248  0
parport                61440  2 parport_pc,ppdev
authenc                16384  2
echainiv               16384  2
esp4                   24576  2
xfrm4_mode_transport    16384  4
tun                    57344  2
xt_REDIRECT            20480  3
ipt_MASQUERADE         20480  2
xt_nat                 16384  2
deflate                16384  0
iptable_nat            16384  1
twofish_generic        20480  0
nf_nat                 49152  4 ipt_MASQUERADE,xt_nat,iptable_nat,xt_REDIRECT
twofish_avx_x86_64     53248  0
twofish_x86_64_3way    28672  1 twofish_avx_x86_64
twofish_x86_64         16384  2 twofish_x86_64_3way,twofish_avx_x86_64
twofish_common         24576  4 twofish_x86_64,twofish_generic,twofish_x86_64_3way,twofish_avx_x86_64
camellia_generic       32768  0
af_packet              53248  10
nf_log_ipv4            16384  1
nf_log_common          16384  1 nf_log_ipv4
xt_LOG                 20480  1
camellia_aesni_avx_x86_64    28672  0
camellia_x86_64        53248  1 camellia_aesni_avx_x86_64
xt_conntrack           16384  2
nf_conntrack          155648  5 xt_conntrack,nf_nat,ipt_MASQUERADE,xt_nat,xt_REDIRECT
nf_defrag_ipv6         24576  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
serpent_avx_x86_64     49152  0
serpent_sse2_x86_64    53248  0
serpent_generic        28672  2 serpent_sse2_x86_64,serpent_avx_x86_64
blowfish_generic       16384  0
blowfish_x86_64        24576  0
blowfish_common        20480  2 blowfish_generic,blowfish_x86_64
cast5_avx_x86_64       49152  0
fuse                  131072  3
cast5_generic          24576  1 cast5_avx_x86_64
cast_common            16384  2 cast5_generic,cast5_avx_x86_64
des_generic            24576  0
cmac                   16384  0
ipt_REJECT             16384  21
nf_reject_ipv4         16384  1 ipt_REJECT
xcbc                   16384  0
rmd160                 20480  0
xt_tcpudp              20480  50
iptable_filter         16384  1
ip_tables              32768  2 iptable_filter,iptable_nat
x_tables               45056  9 xt_conntrack,iptable_filter,xt_LOG,xt_tcpudp,ipt_MASQUERADE,xt_nat,ipt_REJECT,ip_tables,xt_REDIRECT
sha512_ssse3           45056  0
sha512_generic         16384  1 sha512_ssse3
bpfilter               36864  0
af_key                 45056  2
xfrm_algo              16384  2 af_key,esp4
8021q                  40960  0
garp                   16384  1 8021q
mrp                    20480  1 8021q
stp                    16384  1 garp
llc                    16384  2 stp,garp
iscsi_ibft             16384  0
iscsi_boot_sysfs       16384  1 iscsi_ibft
it87                   65536  0
hwmon_vid              16384  1 it87
msr                    16384  0
joydev                 28672  0
hid_generic            16384  0
xfs                  1433600  3
libcrc32c              16384  3 nf_conntrack,nf_nat,xfs
edac_mce_amd           32768  0
kvm_amd               110592  0
ccp                    98304  1 kvm_amd
kvm                   733184  1 kvm_amd
irqbypass              16384  1 kvm
snd_seq_dummy          16384  0
snd_seq_oss            49152  0
snd_emu10k1_synth      20480  0
snd_emux_synth         53248  1 snd_emu10k1_synth
snd_seq_midi_emul      20480  1 snd_emux_synth
snd_seq_virmidi        16384  1 snd_emux_synth
snd_seq_midi           20480  0
snd_seq_midi_event     16384  3 snd_seq_midi,snd_seq_oss,snd_seq_virmidi
raid1                  49152  3
md_mod                167936  3 raid1
crct10dif_pclmul       16384  1
crc32_pclmul           16384  0
ghash_clmulni_intel    16384  0
snd_emu10k1           192512  3 snd_emu10k1_synth
snd_util_mem           16384  2 snd_emu10k1,snd_emux_synth
snd_ac97_codec        147456  1 snd_emu10k1
ac97_bus               16384  1 snd_ac97_codec
snd_hwdep              16384  2 snd_emu10k1,snd_emux_synth
snd_rawmidi            45056  3 snd_seq_midi,snd_emu10k1,snd_seq_virmidi
usbhid                 65536  2
snd_pcm               143360  2 snd_emu10k1,snd_ac97_codec
snd_seq                86016  9 snd_seq_midi,snd_seq_oss,snd_seq_midi_event,snd_seq_virmidi,snd_seq_midi_emul,snd_emux_synth,snd_seq_dummy
aesni_intel           372736  5
snd_seq_device         16384  7 snd_seq,snd_seq_midi,snd_seq_oss,snd_emu10k1,snd_emu10k1_synth,snd_emux_synth,snd_rawmidi
snd_timer              40960  3 snd_seq,snd_emu10k1,snd_pcm
aes_x86_64             20480  1 aesni_intel
crypto_simd            16384  6 camellia_aesni_avx_x86_64,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,cast5_avx_x86_64,twofish_avx_x86_64
cryptd                 28672  5 crypto_simd,ghash_clmulni_intel,aesni_intel
glue_helper            16384  7 camellia_aesni_avx_x86_64,camellia_x86_64,twofish_x86_64_3way,serpent_sse2_x86_64,aesni_intel,serpent_avx_x86_64,twofish_avx_x86_64
8139too                45056  0
snd                   102400  15 snd_seq,snd_seq_device,snd_hwdep,snd_seq_oss,snd_emu10k1,snd_timer,snd_ac97_codec,snd_seq_virmidi,snd_emux_synth,snd_pcm,snd_rawmidi
mxm_wmi                16384  0
pcspkr                 16384  0
k10temp                16384  0
fam15h_power           16384  0
sp5100_tco             20480  0
soundcore              16384  1 snd
8139cp                 36864  0
emu10k1_gp             16384  0
gameport               16384  2 emu10k1_gp
mii                    16384  2 8139cp,8139too
r8169                  94208  0
i2c_piix4              28672  0
radeon               1642496  73
realtek                20480  1
ttm                   114688  1 radeon
libphy                 90112  2 r8169,realtek
drm_kms_helper        212992  1 radeon
button                 20480  0
drm                   487424  14 drm_kms_helper,radeon,ttm
fb_sys_fops            16384  1 drm_kms_helper
syscopyarea            16384  1 drm_kms_helper
sysfillrect            16384  1 drm_kms_helper
sysimgblt              16384  1 drm_kms_helper
i2c_algo_bit           16384  1 radeon
pcc_cpufreq            20480  0
acpi_cpufreq           28672  0
ohci_pci               20480  0
crc32c_intel           24576  5
firewire_ohci          45056  0
firewire_core          77824  1 firewire_ohci
crc_itu_t              16384  1 firewire_core
ehci_pci               20480  0
ohci_hcd               57344  1 ohci_pci
sr_mod                 28672  0
ehci_hcd               98304  1 ehci_pci
cdrom                  73728  1 sr_mod
xhci_pci               20480  0
xhci_hcd              262144  1 xhci_pci
usbcore               303104  9 xhci_hcd,ohci_hcd,ehci_pci,usbhid,ehci_hcd,xhci_pci,ohci_pci
wmi                    32768  1 mxm_wmi
sg                     40960  0
dm_multipath           36864  0
dm_mod                155648  9 dm_multipath
scsi_dh_rdac           16384  0
scsi_dh_emc            16384  0
scsi_dh_alua           20480  0