running qemu-img in guest over a file on shared folder makes system unusable

[Roman Valov]

Steps to reproduce:

1. Install centos-7 guest with latest updates and qemu-img utility
2. Install VirtualBox guest additions as described here: ​https://wiki.centos.org/HowTos/Virtualization/VirtualBox/CentOSguest

3. Setup a shared folder
4. Copy VMDK file onto the shared folder
5. Run following commands in guest:

$ cd /mnt/shared $ qemu-img info <vmdk-file>

Results:

qemu-img exited with errors and any further invocation of standard linux utilities such as ls results into Segmentation fault.

[Socratis]

Replying to reddotr:

qemu-img exited with errors and any further invocation of standard linux utilities such as ls results into Segmentation fault.

1. Please post the exact output of the error, not a generic description that there was an error.

2. Are you a member of the 'vboxsf' group? And you rebooted the Guest after you got yourself into that group?

3. It's usually better and faster, if issues get first addressed in the ​VirtualBox forums, a lot more eyes there. More than 95% of the issues are resolved in the forums, which keeps the developers focusing on the bug fixes and enhancements, and there is no need for another ticket to keep track of. For example, yours is most probably not a bug and someone from the developers has to deal with it and close it as "Invalid".

Plus a discussion and analysis on the bug tracker is going to help me, is going to help you, and potentially a future drive-by user or two. Not so in the forums, many more tend to benefit...

So, please open a new thread in the ​Linux Guests section of the forums. Please be sure to mention that you came from the bug tracker and include the ticket number.

4. You were supposed to follow these steps when you filed the bug, and provide a VBox.log:

   Attach a (full) log file ("Machine" menu/"Show Log" in the main VirtualBox Manager window) straight away to save time for you and for us. The log file contains a lot of useful information about both the host and the guest systems as well as information about what happened during a particular machine run. Please do not cut and paste it.

[Frank Batschulat (Oracle)]

cannot reproduce:

Oracle Linux Server 7.7"
 
[fbatschu@ol7 ~]$ ls -la /media/sf_Downloads/Solaris-Trunk-disk001.vdi
-rwxrwx---. 1 root vboxsf 57237569536 Nov 13 11:32 /media/sf_Downloads/Solaris-Trunk-disk001.vdi
 
qemu-img version 1.5.3, Copyright (c) 2004-2008 Fabrice Bellard
 
[fbatschu@ol7 ~]$ qemu-img info /media/sf_Downloads/Solaris-Trunk-disk001.vdi
image: /media/sf_Downloads/Solaris-Trunk-disk001.vdi
file format: vdi
virtual size: 64G (68719476736 bytes)
disk size: 53G
cluster_size: 1048576
 
Linux 4.14.35-1902.7.3.el7uek.x86_64 (ol7) 	11/18/2019 	_x86_64_	(2 CPU)
KiB Mem :  6861780 total,  5206996 free,   787132 used,   867652 buff/cache
 
https://www.osboxes.org/linux-mint/#linux-mint-19-2-vmware
 
[fbatschu@ol7 ~]$ ls -la /media/sf_Downloads/M19_2-64bit.7z.vmdk
-rwxrwx---. 1 root vboxsf 1466949746 Nov 18 14:40 /media/sf_Downloads/M19_2-64bit.7z.vmdk
 
[fbatschu@ol7 ~]$ qemu-img info /media/sf_Downloads/M19_2-64bit.7z.vmdk
image: /media/sf_Downloads/M19_2-64bit.7z.vmdk
file format: raw
virtual size: 1.4G (1466950144 bytes)
disk size: 1.4G
 
===============================================
 
Fedora 31 (Workstation Edition)
 
Linux 5.3.11-300.fc31.x86_64 (localhost.localdomain) 	11/18/2019 _x86_64_	(2 CPU)
MiB Mem :   6954.0 total,   5078.4 free,    853.5 used,   1022.1 buff/cache
 
[fbatschu@localhost ~]$ ls -la /media/sf_Downloads/M19_2-64bit.7z.vmdk
-rwxrwx---. 1 root vboxsf 1466949746 Nov 18 14:40 /media/sf_Downloads/M19_2-64bit.7z.vmdk
 
[fbatschu@localhost ~]$ qemu-img info /media/sf_Downloads/M19_2-64bit.7z.vmdk
image: /media/sf_Downloads/M19_2-64bit.7z.vmdk
file format: raw
virtual size: 1.37 GiB (1466950144 bytes)
disk size: 1.37 GiB
 
[fbatschu@localhost ~]$ ls -la /media/sf_Downloads/Solaris-Trunk-disk001.vdi
-rwxrwx---. 1 root vboxsf 57237569536 Nov 13 11:32 /media/sf_Downloads/Solaris-Trunk-disk001.vdi
 
[fbatschu@localhost ~]$ qemu-img info /media/sf_Downloads/Solaris-Trunk-disk001.vdi
image: /media/sf_Downloads/Solaris-Trunk-disk001.vdi
file format: vdi
virtual size: 64 GiB (68719476736 bytes)
disk size: 53.3 GiB
cluster_size: 1048576

Please re-open when you have a reproducable test case and configuration informations available

[Frank Batschulat (Oracle)]

Also I cannot reproduce on CentOS7 either:

[fbatschu@centos7 ~]$ uname -a
Linux centos7 3.10.0-1062.4.3.el7.x86_64 #1 SMP Wed Nov 13 23:58:53 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
[fbatschu@centos7 ~]$ cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"

[fbatschu@centos7 ~]$ ls -la /media/sf_Downloads/M19_2-64bit.7z.vmdk 
-rwxrwx---. 1 root vboxsf 1466949746 Nov 18 14:40 /media/sf_Downloads/M19_2-64bit.7z.vmdk
[fbatschu@centos7 ~]$ qemu-img info /media/sf_Downloads/M19_2-64bit.7z.vmdk 
image: /media/sf_Downloads/M19_2-64bit.7z.vmdk
file format: raw
virtual size: 1.4G (1466950144 bytes)
disk size: 1.4G