freebsd stable - May 2021 - Loading zfs module results in hangup on i386

From: Yasuhiro Kimura <yasu at utahime.org>
Subject: Install of 13.0-RELEASE i386 with ZFS root hangs up
Date: Fri, 07 May 2021 21:47:59 +0900 (JST)
> Hello,
> 
> Does anyone succeed to install 13.0-RELEASE i386 with ZFS root?
> 
> I tried this with VirtualBox and VMware Player on Windows with
> following VM condition.
> 
> * 4 CPUs
> * 8GB memory
> * 100GB disk
> * Bridge mode NIC
> 
> But in both cases, VM gets high CPU load and hangs up after I moved
> to 'YES' at 'ZFS Configuration' menu and type return key.
> 
> If I select UFS root installation completes successfully. So the
> problem is specific to ZFS root.
Now I think I know what is the source of problem. After all, on
13.0-RELEASE i386 system simply loading zfs module results in system
hang up.

The steps to reproduce it are,

1. Boot with install media of 13.0-RELEASE i386
2. At the first menu of FreeBSD installer, select 'Shell'.
3. At the shell prompt, type `kldload zfs` and return key.

I confirmed hangup happens with VirtualBox, VMware Player and my bare
metal PC environement. So the problem doesn't depend on hardware.

And hangup also happens with 13-STABLE and 14-CURRENT.

---
Yasuhiro Kimura

From: Yasuhiro Kimura <yasu at utahime.org>
Subject: Loading zfs module results in hangup on i386 (Re: Install of
13.0-RELEASE i386 with ZFS root hangs up)
Date: Sat, 08 May 2021 07:31:47 +0900 (JST)
> Now I think I know what is the source of problem. After all, on
> 13.0-RELEASE i386 system simply loading zfs module results in system
> hang up.
> 
> The steps to reproduce it are,
> 
> 1. Boot with install media of 13.0-RELEASE i386
> 2. At the first menu of FreeBSD installer, select 'Shell'.
> 3. At the shell prompt, type `kldload zfs` and return key.
> 
> I confirmed hangup happens with VirtualBox, VMware Player and my bare
> metal PC environement. So the problem doesn't depend on hardware.
> 
> And hangup also happens with 13-STABLE and 14-CURRENT.
This problem is already reported to Bugzilla.

Bug 254177 When ZFS is recognized, An i386 machine with a lot of memory hangs.
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254177

---
Yasuhiro Kimura