XPost: linux.debian.bugs.dist   
   From: carnil@debian.org   
      
   Control: tags -1 + moreinfo   
      
   On Mon, Oct 27, 2025 at 01:53:19PM +0100, Jan Stolarek wrote:   
   > Package: src:linux   
   > Version: 6.12.48-1   
   > Severity: important   
   > X-Debbugs-Cc: debian-amd64@lists.debian.org, jan.stolarek@mailbox.org   
   > User: debian-amd64@lists.debian.org   
   > Usertags: amd64   
   >   
   > Dear Maintainer,   
   >   
   > When trying to run Debian Trixie as a guest OS in a VM, I ran into major   
   issues   
   > that make Trixie unusable in a virtualized environment.   
   >   
   > I am using Debian Trixie as a host (same as guest) and VirtualBox 7.2   
   available   
   > in Trixie repositories.  I created a new virtual machine, selected   
   > debian-13.1.0-amd64-netinst.iso as the installation media (obtained from   
   debian   
   > servers, MD5: a9d5c5778f6e228af1e462d717a6d544), and performed a basic Trixie   
   > installation in text mode.  I went with a single-partition installation with   
   no   
   > desktop environment; during the Software selection step I only selected "SSH   
   > server" and "standard system utilities".  After the installation I added a   
   > handful of tools such as aptitude, mc, emacs-nox, vim and htop.    
   Essentially, it   
   > is a text-only environment that I want to be able to SSH into.   
   >   
   > However, the guest system is highly unstable.  Usually, after a couple of   
   > minutes of uptime, it becomes unresponsive with kernel errors being reported   
   on   
   > TTY1:   
   >   
   >   [  325.455294] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:   
   >   [  325.455336] rcu:       9-...!: (1 ticks this GP) idle=a678/0/0x0   
   softirq=1084/1085 fqs=0 (false positive?)   
   >   [  325.455356] rcu:       10-...!: (19 ticks this GP) idle=8460/0/0x0   
   softirq=821/823 fqs=0 (false positive?)   
   >   [  325.455382] rcu:       13-...!: (0 ticks this GP) idle=2fe0/0/0x0   
   softirq=687/687 fqs=0 (false positive?)   
   >   [  325.455399] rcu:       15-...!: (0 ticks this GP) idle=3bf0/0/0x0   
   softirq=1160/1160 fqs=0 (false positive?)   
   >   [  325.455416] rcu:       (detected by 7, t=5260 jiffies, g=11081, q=2672   
   ncpus=16)   
   >   
   > Detailed call traces van be found in dmesg:   
   >   
   >   [  325.455437] Sending NMI from CPU 7 to CPUs 9:   
   >   [  325.455458] NMI backtrace for cpu 9   
   >   [  325.455462] CPU: 9 UID: 0 PID: 0 Comm: swapper/9 Not tainted   
   6.12.48+deb13-amd64 #1  Debian 6.12.48-1   
   >   [  325.455465] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS   
   VirtualBox 12/01/2006   
   >   [  325.455467] RIP: 0010:pv_native_safe_halt+0xf/0x20   
   >   [  325.455478] Code: 09 e9 50 bd 20 00 0f 1f 44 00 00 90 90 90 90 90 90 90   
   90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 05 29 31 00 fb f4    
   27 bd 20 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90   
   >   [  325.455479] RSP: 0018:ffffb5d6c010bed8 EFLAGS: 00000202   
   >   [  325.455482] RAX: 0000000000000009 RBX: ffff9c92409d0000 RCX:   
   ffff9c924b148860   
   >   [  325.455484] RDX: 0000000000000000 RSI: 0000000000000009 RDI:   
   00000000000da674   
   >   [  325.455485] RBP: 0000000000000009 R08: 0000000000000001 R09:   
   0000000000000001   
   >   [  325.455486] R10: 0000000000000009 R11: 0000000000000001 R12:   
   0000000000000000   
   >   [  325.455487] R13: 0000000000000000 R14: 0000000000000000 R15:   
   0000000000000000   
   >   [  325.455488] FS:  0000000000000000(0000) GS:ffff9c99b4480000(0000)   
   knlGS:0000000000000000   
   >   [  325.455490] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033   
   >   [  325.455499] CR2: 00007f0c46000010 CR3: 0000000108326000 CR4:   
   00000000000506f0   
   >   [  325.455502] Call Trace:   
   >   [  325.455510]     
   >   [  325.455511]  default_idle+0x9/0x20   
   >   [  325.455521]  default_idle_call+0x29/0x100   
   >   [  325.455523]  do_idle+0x1fe/0x240   
   >   [  325.455538]  cpu_startup_entry+0x29/0x30   
   >   [  325.455540]  start_secondary+0x11e/0x140   
   >   [  325.455551]  common_startup_64+0x13e/0x141   
   >   [  325.455557]     
   >   
   > I will attach full dmesg log in a follow-up email.   
   >   
   > I attempted to resolve the problem by changing the default virtual machine   
   > settings, in particular:   
   >   
   >   - enabling PAE/NX   
   >   - enabling Nested VT-x/AMD-V   
   >   - disabling Nested Paging   
   >   - changing the graphics controller   
   >   - installing VirtualBox Guest Addons inside the guest OS   
   >   
   > None of these changes had any effect.   
   >   
   > At this point, Debian Trixie seems unusable with VirtualBox.  I will attempt   
   to   
   > create a Trixie VM with QEmu and see whether that works.  I also note, that   
   on   
   > the same host machine I have a Debian Buster virtual machine running under   
   > VirtualBox without any issues.  Lastly, I managed to report the bug from   
   inside   
   > the VM, so information that follows is accurate w.r.t. the problematic guest   
   > system.   
   >   
   > Please let me know if any further details are required.   
      
   We suspect this is actually a virtualbox issue. Please thus test this   
   under Qemu. Does the issue reproduce there?   
      
   Regards,   
   Salvatore   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)