MVM FAQs

Info Box Applies to MVM

Configuration

Q: VirtualBox manager reports the "The shared folder 'xyz' could not be set up" when starting the MVM. How to fix it?

This kind of error is due to an incorrect path of the folder(s) shared between the host and the guest machines. The following image shows an example of such an error.

To fix it, just remove the erroneous shared folders as depicted in the following image.

Q: How to configure the network interface of the MVM?

Please refer to this page.

Q: How to change the keyboard layout of Lightweight X11 Desktop Environment (LXDE)?

To change the keyboard layout, open a terminal (CTRL+ALT+T) and run the following command:

sudo dpkg-reconfigure keyboard-configuration

Follow the on-screen instruction to select the desired keyboard layout

Q: How to use the USB devices connected to the host machine?

By default, the USB controller of the MVM (guest machine) is not enabled. To enable it, in the VM VirtualBox Manager right click on the selected MVM end open the Settings item. Them, select the USB item and configure it as shown in the following image.

The USB devices which are physically connected to the host machine can be connected to the guest machine with the Devices->USB menu, as shown in the following image.

Q: I can't start make menuconfig. How to fix it?

If the following error is encountered when trying to configure the Linux kernel via menuconfig

dvdk@vagrant-ubuntu-trusty-64:~/lynx/linux$ make O=../linux-build/ menuconfig
  GEN     /home/dvdk/lynx/linux-build/Makefile
 *** Unable to find the ncurses libraries or the
 *** required header files.
 *** 'make menuconfig' requires the ncurses libraries.
 *** 
 *** Install ncurses (ncurses-devel) and try again.
 *** 
make[2]: *** [scripts/kconfig/dochecklxdialog] Error 1
make[1]: *** [menuconfig] Error 2
make: *** [sub-make] Error 2

, required libraries are missing.

Please install the following packages:

• libncurses5-dev
• libncursesw5-dev.

Q: Is it possible to resize the virtual disk?

Yes, but you need to convert the image to VDI format first. For example, see this page.

Once you have the VDI file, follow the procedure described here.

Q: I get an OpenSSL error when accessing resources over TLS, e.g. download using wget on https. How to fix this?

This errors is caused when an old version of OpenSSL, e.g. like the one present on an non-updated Ubuntu 12.04, is used to access resources using TLS, e.g.:

dvdk@dvdkVM:~$ wget https://github.com/openssl/openssl/archive/master.zip
--2018-11-15 22:59:47--  https://github.com/openssl/openssl/archive/master.zip
Resolving github.com (github.com)... 140.82.118.3, 140.82.118.4
Connecting to github.com (github.com)|140.82.118.3|:443... connected.
OpenSSL: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
Unable to establish SSL connection.

To fix this user just have to updates OpenSSL and related libraries, using the following commands:

sudo apt-get update
sudo apt-get install libssl-dev curl wget openssl

This is the result:

dvdk@dvdkVM:~$ wget https://github.com/openssl/openssl/archive/master.zip
--2018-11-15 23:02:38--  https://github.com/openssl/openssl/archive/master.zip
Resolving github.com (github.com)... 140.82.118.4, 140.82.118.3
Connecting to github.com (github.com)|140.82.118.4|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://codeload.github.com/openssl/openssl/zip/master [following]
--2018-11-15 23:02:39--  https://codeload.github.com/openssl/openssl/zip/master
Resolving codeload.github.com (codeload.github.com)... 192.30.253.120, 192.30.253.121
Connecting to codeload.github.com (codeload.github.com)|192.30.253.120|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/zip]
Saving to: `master.zip'

    [    <=>                                                                                                                                ] 652.482      694K/s

Q: Buffer I/O Error when accessing USB devices

When trying to write a large file on a USB device (e.g. micro SD, connected to the MVM through an adapter) user may experience some Buffer I/O errors (followed by additional kernel errors, depending on the specific operation that caused the error) like the following (use dmesg on a terminal to see the kernel log buffer)

[  358.392710]  sdb: sdb1 sdb2
[  880.588382] EXT4-fs (sdb2): mounting ext3 file system using the ext4 subsystem
[  881.046203] EXT4-fs (sdb2): mounted filesystem with ordered data mode. Opts: (null)
[ 1008.759054] usb 1-1: USB disconnect, device number 2
[ 1008.778105] blk_update_request: I/O error, dev sdb, sector 19338752 op 0x1:(WRITE) flags 0x4000 phys_seg 14 prio class 0
[ 1008.778116] blk_update_request: I/O error, dev sdb, sector 19091736 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[ 1008.778119] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386468)
[ 1008.778121] Buffer I/O error on device sdb2, logical block 289315
[ 1008.778128] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386469)
[ 1008.778128] Buffer I/O error on device sdb2, logical block 289316
[ 1008.778130] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386470)
[ 1008.778130] Buffer I/O error on device sdb2, logical block 289317
[ 1008.778132] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386471)
[ 1008.778133] Buffer I/O error on device sdb2, logical block 289318
[ 1008.778135] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386472)
[ 1008.778136] Buffer I/O error on device sdb2, logical block 289319
[ 1008.778138] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386473)
[ 1008.778138] Buffer I/O error on device sdb2, logical block 289320
[ 1008.778140] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386474)
[ 1008.778140] Buffer I/O error on device sdb2, logical block 289321
[ 1008.778141] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386475)
[ 1008.778142] Buffer I/O error on device sdb2, logical block 289322
[ 1008.778144] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386476)
[ 1008.778144] Buffer I/O error on device sdb2, logical block 289323
[ 1008.778146] EXT4-fs warning (device sdb2): ext4_end_bio:311: I/O error 10 writing to inode 853990 (offset 0 size 0 starting block 2386477)
[ 1008.778146] Buffer I/O error on device sdb2, logical block 289324
[ 1008.778208] blk_update_request: I/O error, dev sdb, sector 19338992 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
[ 1008.778222] blk_update_request: I/O error, dev sdb, sector 19358224 op 0x1:(WRITE) flags 0x0 phys_seg 11 prio class 0
[ 1008.778262] blk_update_request: I/O error, dev sdb, sector 19091976 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[ 1008.778282] blk_update_request: I/O error, dev sdb, sector 19092216 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[ 1008.778317] blk_update_request: I/O error, dev sdb, sector 44090904 op 0x1:(WRITE) flags 0x0 phys_seg 10 prio class 0
[ 1008.778325] blk_update_request: I/O error, dev sdb, sector 19092456 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[ 1008.778356] blk_update_request: I/O error, dev sdb, sector 19339136 op 0x1:(WRITE) flags 0x0 phys_seg 8 prio class 0
[ 1008.778364] blk_update_request: I/O error, dev sdb, sector 19358464 op 0x1:(WRITE) flags 0x4000 phys_seg 15 prio class 0
[ 1008.778423] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 13, block_bitmap = 425984
[ 1008.778456] Buffer I/O error on dev sdb2, logical block 0, lost sync page write
[ 1008.778458] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.778558] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 14, block_bitmap = 458752
[ 1008.778615] Buffer I/O error on dev sdb2, logical block 0, lost sync page write
[ 1008.778617] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.778626] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 15, block_bitmap = 491520
[ 1008.778677] Buffer I/O error on dev sdb2, logical block 0, lost sync page write
[ 1008.778678] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.778686] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 16, block_bitmap = 524288
[ 1008.778735] Buffer I/O error on dev sdb2, logical block 0, lost sync page write
[ 1008.778737] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.778744] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 17, block_bitmap = 557056
[ 1008.778826] Buffer I/O error on dev sdb2, logical block 0, lost sync page write
[ 1008.778828] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.839764] Buffer I/O error on dev sdb2, logical block 131072, lost async page write
[ 1008.839769] Buffer I/O error on dev sdb2, logical block 164865, lost async page write
[ 1008.839776] Buffer I/O error on dev sdb2, logical block 196608, lost async page write
[ 1008.839778] Buffer I/O error on dev sdb2, logical block 230401, lost async page write
[ 1008.839795] Buffer I/O error on dev sdb2, logical block 2818048, lost async page write
[ 1008.841976] JBD2: Detected IO errors while flushing file data on sdb2-8
[ 1008.842006] Aborting journal on device sdb2-8.
[ 1008.842011] JBD2: Error -5 detected when updating journal superblock for sdb2-8.
[ 1008.842130] JBD2: Detected IO errors while flushing file data on sdb2-8
[ 1008.851777] EXT4-fs (sdb2): I/O error while writing superblock
[ 1008.851780] EXT4-fs error (device sdb2): ext4_journal_check_start:61: Detected aborted journal
[ 1008.851780] EXT4-fs (sdb2): Remounting filesystem read-only
[ 1008.921620] JBD2: Error while async write back metadata bh 131072.
[ 1008.921621] JBD2: Error while async write back metadata bh 164865.
[ 1008.921624] JBD2: Error while async write back metadata bh 196608.
[ 1008.921649] JBD2: Error while async write back metadata bh 230401.
[ 1008.921864] JBD2: Error while async write back metadata bh 2818048.
[ 1008.922181] JBD2: Error while async write back metadata bh 2818637.
...
[ 1008.924465] JBD2: Error while async write back metadata bh 3408720.
[ 1008.924467] JBD2: Error while async write back metadata bh 3408721.
[ 1009.027187] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 12, block_bitmap = 393216
[ 1009.027191] EXT4-fs error (device sdb2): ext4_discard_preallocations:4113: comm tar: Error -5 reading block bitmap for 12
[ 1009.027193] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 12, block_bitmap = 393216
[ 1009.027194] EXT4-fs error (device sdb2): ext4_discard_preallocations:4113: comm tar: Error -5 reading block bitmap for 12
[ 1009.027200] EXT4-fs error (device sdb2): ext4_wait_block_bitmap:519: comm tar: Cannot read block bitmap - block_group = 18, block_bitmap = 589824
[ 1014.162995] EXT4-fs error: 30 callbacks suppressed
[ 1014.162997] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163016] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163160] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163163] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163178] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163181] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163192] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163194] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163204] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1014.163207] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736540] EXT4-fs error: 4649 callbacks suppressed
[ 1020.736541] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736679] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736707] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736733] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736741] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736909] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736917] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736946] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.736955] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1020.737113] EXT4-fs error (device sdb2): __ext4_find_entry:1577: inode #819201: comm tar: reading directory lblock 0
[ 1022.476182] EXT4-fs warning: 33909 callbacks suppressed
[ 1022.476184] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476187] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476189] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476192] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476193] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476196] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476198] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476200] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476202] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block
[ 1022.476204] EXT4-fs warning (device sdb2): dx_probe:786: inode #851989: lblock 0: comm tar: error -5 reading directory block

The root cause of the problem may vary (e.g. Windows host OS device drivers, host hardware issue, Virtual Box incompatibility with host OS and so on) but, in our experience, this is caused by poor USB device or SD card reader.

For this reason, as first action we suggest to change SD card adapter with a more robust one

E.g. we've found that simple adapters like the one in the following picture, most of the time shows this kind of error during the creation of bootable SD card (like the one described in this article)

Q: OE Sanity check failed with Fetcher failure for URL: 'https://eula-downloads.yoctoproject.org/index.php'

This usually happens from 1st October 2023 on Ubuntu 14.04 and Ubuntu 16.04 based MVM and the root cause is the DST Root CA X3 certificate expiration (see for example this superuser thread)

Without involving bitbake and Yocto, this can be easily reproduced with a curl command, here showed with it's error output:

bash# curl https://eula-downloads.yoctoproject.org/index.php

curl: (60) SSL certificate problem: certificate has expired
More details here: http://curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
 of Certificate Authority (CA) public keys (CA certs). If the default
 bundle file isn't adequate, you can specify an alternate file
 using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
 the bundle, the certificate verification probably failed due to a
 problem with the certificate (it might be expired, or the name might
 not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
 the -k (or --insecure) option.

The easy way to fix this is to disable the expired certificate the the following command (please note that it must be run with sudo)

sudo sed -i '/^mozilla\/DST_Root_CA_X3.crt$/ s/^/!/' /etc/ca-certificates.conf && sudo update-ca-certificates

This is a persistent change on the MVM, so you'll need to perform it only once

After applying the fix, the curl command now succeed

bash# curl https://eula-downloads.yoctoproject.org/index.php
<html>
<head><title>301 Moved Permanently</title></head>
<body bgcolor="white">
<center><h1>301 Moved Permanently</h1></center>
<hr><center>nginx/1.14.2</center>
</body>
</html>