shut down realm VM when it is large enough

Hi all, I am working with cca-full/v3 branch of linux-cca along with cca/v3 of qemu to create realm VM. I also use shrinkwrap which downloads and uses the latest version of TF-RMM and TF-A. What I faced is the below error after running poweroff command inside the realm that is 1750MB in size:

Stopping dropbear sshd: OK

Stopping network: OK                                                                                                     

Seeding 256 bits and crediting                                                                                        

Saving 256 bits of creditable seed for next boot                                                                

Stopping klogd: OK                                                                                                    

Stopping syslogd: OK                                                                                                   

umount: devtmpfs busy - remounted read-only                                                                     

umount: can't unmount /: Invalid argument                                                                          

The system is going down NOW!                                                                                          

Sent SIGTERM to all processes                                                                                             

Sent SIGKILL to all processes                                                                                     

Requesting system poweroff                                                                                                      

[  136.359191] reboot: Power [  390.934735] rcu: INFO: rcu_preempt self-detected stall on CPU                

[  390.934817] rcu:     1-....: (20999 ticks this GP) idle=1b3c/1/0x4000000000000000 softirq=426/426 fqs=5249                                                                                                                                           

[  390.934993] rcu:     (t=21000 jiffies g=549 q=10 ncpus=8)                                                    

[  390.935093] CPU: 1 PID: 189 Comm: qemu-system-aar Not tainted 6.10.0-rc1-g d901c27a #1                    

[  390.935226] Hardware name: FVP Base RevC (DT)                                                                

[  390.935302] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=-)                                  

[  390.935436] pc : realm_unmap_range_private+0x29c/0x2a0                                                                                

[  390.935556] lr : realm_unmap_range_private+0x298/0x2a0                                                                               

[  390.935676] sp : ffff800080d8ba30                                                                                   

[  390.935746] x29: ffff800080d8ba30 x28: 0000000000000000 x27: 000000009910f000                                

[  390.935929] x26: 000f800000000000 x25: 0000010000000000 x24: 0010000000000000                                

[  390.936116] x23: ffffffffffffffff x22: 00000000c4000155 x21: 0000000880bcc000                                                      

[  390.936301] x20: ffff800080135df0 x19: 000000009910e000 x18: 0000000000000001                               

[  390.936485] x17: 0000000000000000 x16: 0000000000800006 x15: 0000000000000000                                

[  390.936665] x14: 0000000000000002 x13: 0000000000000002 x12: 0000000000054c3f                                 

[  390.936843] x11: 0000000000000000 x10: ffff000801ace80c x9 : 0000000000000800                                

[  390.937026] x8 : 0000000000000820 x7 : 0000000000000000 x6 : 0000000000000000                                

[  390.937203] x5 : 000f000800bcc000 x4 : 00000000995de000 x3 : 0000000000000000                                

[  390.937385] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000                                

[  390.937562] Call trace:                                                                                                     

[  390.937619]  realm_unmap_range_private+0x29c/0x2a0                                                                        

[  390.937741]  kvm_realm_unmap_range+0x134/0x138                                                                          

[  390.937861]  __unmap_stage2_range+0x60/0x7c                                                                  

[  390.937990]  kvm_free_stage2_pgd+0xa0/0xd4                                                                  

[  390.938127]  kvm_arch_flush_shadow_all+0x1c/0x34                                                             

[   390.938269]  kvm_mmu_notifier_release+0x30/0x84                                                                         

[  390.938409]  __mmu_notifier_release+0x78/0x1e0                                                              

[  390.938551]  exit_mmap+0x270/0x288                                                                                 

[  390.938665]  __mmput+0x38/0x154                                                                                    

[  390.938795]  mmput+0x50/0x5c                                                                                    

[  390.938921]  do_exit+0x26c/0x904                                                                                     

[  390.939035]  do_group_exit+0x34/0x90                                                                         

[  390.939147]  pid_child_should_wake+0x0/0x5c                                                                  

[  390.939274]  invoke_syscall+0x48/0x118                           

[  390.939410]  el0_svc_common.constprop.0+0x40/0xe0                                                                       

[  390.939557]  do_el0_svc+0x1c/0x28                                                                                   

[  390.939689]  el0_svc+0xac/0xdc                                                                                  

[  390.939820]  el0t_64_sync_handler+0x100/0x12c                                                             

[  390.939966]  el0t_64_sync+0x190/0x194   

Worth to mention I did not see similar error for a normal world VM of size 1750MB, moreover I did not see this error with realm VM that is 450MB. Therefore, it should be somehow related to memory management of realm VMs when their size is greater than a threshold.

Cheers,

Sina