CURRENT panics while booting on HiFive Unmatched Rev. B

Dear all,

any idea what could be wrong? This is a checkout of CURRENT from a couple of hours ago.

Here is the output on the console:

Loading kernel...                                                              
/boot/kernel/kernel text=0x60a95e text=0x1aa838 data=0x1290c0 data=0xf58+0x2873a8 0x8+0x132e70+0x8+0x11dd56
Loading configured modules...
/boot/entropy size=0x1000
/etc/hostid size=0x25
Using DTB provided by EFI at 0x87ef6000.
Kernel entry at 0xf6800030...
Kernel args: (null)
Loading splash ok
---<<BOOT>>---
GDB: debug ports: uart
GDB: current port: uart
KDB: debugger backends: ddb gdb
KDB: current backend: ddb
Copyright (c) 1992-2025 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 15.0-CURRENT #0 main-n276381-b2f4d9b67f31: Fri Apr 11 15:42:40 CEST 2025
   root@riscv.nplab.de:/usr/obj/home/tuexen/freebsd-src/riscv.riscv64/sys/GENERIC riscv
FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
WARNING: WITNESS option enabled, expect reduced performance.
  t[0]: 0x0000000000000001
  t[1]: 0xffffffc000a79770 (thread0_st + 0x170)
  t[2]: 0xffffffc000af0880 (w_locklistdata + 0x43f80)
  t[3]: 0xffffffc000af2d00 (w_lohash)
  t[4]: 0x0000000000000084
  t[5]: 0x0000000000000000
  t[6]: 0x0000000000000002
  s[0]: 0xffffffc000003a20 (initstack + 0x3870)
  s[1]: 0xffffffd3e67d2000
  s[2]: 0x0000000000000000
  s[3]: 0x0000000000000000
  s[4]: 0xffffffc000b61b18 (vm_dom + 0x218)
  s[5]: 0xffffffc000695490 ($d + 0x10b8)
  s[6]: 0x0000000000000e72
  s[7]: 0xffffffc000b61c04 (vm_dom + 0x304)
  s[8]: 0x0000000000000a23
  s[9]: 0xffffffc000b61900 (vm_dom)
 s[10]: 0xffffffc0008e2630 (pageproc)
 s[11]: 0x0000000000000000
  a[0]: 0xffffffd000000000
  a[1]: 0x0000000000000000
  a[2]: 0x0000000000000fff
  a[3]: 0xffffffd000000000
  a[4]: 0xffffffd000000001
  a[5]: 0x0000000000010000
  a[6]: 0xffffffc000808ad0 (lock_class_mtx_sleep)
  a[7]: 0x4000000000000000
    ra: 0xffffffc0005e6b02 (pmap_zero_page + 0x38)
    sp: 0xffffffc000003a10 (initstack + 0x3860)
    gp: 0xffffffc0008dfa58 (__global_pointer$)
    tp: 0xffffffc000b63bc0 (__pcpu)
  sepc: 0xffffffc0005d71d0 (memset + 0x12)
sstatus: 0x8000000200006100
stval  : 0xffffffd000000000
panic: Memory access exception at 0xffffffc0005d71d0: 0xffffffd000000000
cpuid = 0
time = 1
KDB: stack backtrace:
db_trace_self() at db_trace_self
db_trace_self_wrapper() at db_trace_self_wrapper+0x36
kdb_backtrace() at kdb_backtrace+0x2c
vpanic() at vpanic+0x16e
panic() at panic+0x26
do_trap_supervisor() at do_trap_supervisor+0x108
cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x74
--- exception 7, tval = 0xffffffd000000000
memset() at memset+0x12
pmap_zero_page() at pmap_zero_page+0x34
vm_page_alloc_noobj_domain() at vm_page_alloc_noobj_domain+0x240
uma_small_alloc() at uma_small_alloc+0x66
keg_alloc_slab() at keg_alloc_slab+0xb0
zone_import() at zone_import+0xf6
zone_alloc_item() at zone_alloc_item+0x68
zone_ctor() at zone_ctor+0x542
uma_startup1() at uma_startup1+0x184
vm_mem_init() at vm_mem_init+0x3c
mi_startup() at mi_startup+0x1ee
va() at va+0x60
KDB: enter: panic
[ thread pid 0 tid 0 ]
Stopped at      kdb_enter+0x3a: sd      zero,1890(s1)
db> 

Best regards
Michael