Re: port-xen/58561 (panic: kernel diagnostic assertion, "x86_read_psl() == 0" failed: file, "/home/netbsd/10/src/sys/arch/x86/x86/pmap.c", line 3581)

[Konrad Schroder <perseant%hhhh.org@localhost>]

I can reliably reproduce this issue, quickly enough that a NetBSD 
tools+release build usually will not complete before the system panics.  
I am using yesterday's -current, with a kernel config as follows:

    netbsd# cat sys/arch/amd64/conf/LFS
    include "arch/amd64/conf/XEN3_DOMU"

    options         LOCKDEBUG

The host system is Ubuntu 22.04.5 running xen-hypervisor-4.16-amd64, and 
the guest config is:

    linux# cat lfs
    name = "lfs"
    kernel = "/etc/xen/netbsd-lfs.gz"
    memory = 16384
    vcpus = 2
    vif = [ 'bridge=br0' ]
    disk = [ '/dev/md3p6,raw,hda,rw' ]

    on_poweroff = 'destroy'
    on_reboot   = 'destroy'
    on_crash    = 'destroy'

The load running on the system is from

    ./build.sh -j4 -U -u -O obj.amd64 tools release

in a freshly unpacked src.

If I configure the VM with "vcpus = 1", or turn off LOCKDEBUG, it 
doesn't panic.

(As the names imply, I'm hoping to use this configuration to test LFS, 
but the problem is unrelated: the system panics without any LFS file 
system ever having been active since boot.)

The panic traces vary, but are consistent after the call to copyout():

    [ 842.2695658] panic: kernel diagnostic assertion "(psl = 
x86_read_psl()) == 0" failed: file 
"/home/src-current/sys/arch/x86/x86/pmap.c", line 3596 psl=0x1
    [ 842.2695658] cpu1: Begin traceback...
    [ 842.2695658] vpanic() at netbsd:vpanic+0x164
    [ 842.2695658] kern_assert() at netbsd:kern_assert+0x4b
    [ 842.2695658] pmap_load() at netbsd:pmap_load+0x13d
    [ 842.2695658] do_pmap_load() at netbsd:do_pmap_load+0x1d
    [ 842.2695658] copyout() at netbsd:copyout+0x48
    [ 842.2695658] ubc_uiomove() at netbsd:ubc_uiomove+0x12e
    [ 842.2695658] ffs_read() at netbsd:ffs_read+0xf0
    [ 842.2695658] VOP_READ() at netbsd:VOP_READ+0x3c
    [ 842.2695658] vn_rdwr() at netbsd:vn_rdwr+0x100
    [ 842.2695658] vmcmd_readvn() at netbsd:vmcmd_readvn+0x56
    [ 842.2695658] execve_runproc() at netbsd:execve_runproc+0x34e
    [ 842.2695658] execve1() at netbsd:execve1+0x4c
    [ 842.2695658] sys_execve() at netbsd:sys_execve+0x2a
    [ 842.2695658] syscall() at netbsd:syscall+0x98
    [ 842.2695658] --- syscall (number 59) ---
    [ 842.2695658] netbsd:syscall+0x98:
    [ 842.2695658] cpu1: End traceback...

Let me know if there is anything you'd like me to do to help test or 
further diagnose the issue.

Thanks,

Konrad Schroder
perseant%hhhh.org@localhost