Created attachment 864078 [details]
processes in blocked state

I was unable to set up kdump properly (see bug 1207114).

This was reported upstream as:
https://lore.kernel.org/all/b8017e09-f336-3035-8344-c549086c2340@kernel.org/

After I updated the host from 6.0 to 6.1 (being at 6.1.4 ATM), my qemu 
VMs started stalling (and the host at the same point too). It doesn't 
happen right after boot, maybe a suspend-resume cycle is needed (or 
longer uptime, or a couple of qemu VM starts, or ...). But when it 
happens, it happens all the time till the next reboot.

Older guest's kernels/distros are affected as well as Win10.

In guests, I see for example stalls in memset_orig or 
smp_call_function_many_cond.

qemu-kvm-7.1.0-13.34.x86_64.

I dumped blocked tasks (sysrq-w) on _host_ and 
everything seems to stall on mmap_read_lock() or 
mmap_write_lock_killable().

There should be enough free memory (note caches at 8G):
                total        used        free      shared  buff/cache 
available
Mem:            15Gi        10Gi       400Mi       2,5Gi       8,0Gi 
   5,0Gi
Swap:             0B          0B          0B


I rmmoded kvm-intel now, so:
   qemu-kvm: failed to initialize kvm: No such file or directory
   qemu-kvm: falling back to tcg
and it behaves the same (more or less expected).