Panic on current on mac68k

On a Quadra 605 which has been running netbsd-8 without issues for ages, 
it seems -current isn't happy. I don't see any obvious recent changes 
which might cause this. Ideas?

[   1.0000000] Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 
2003, 2004, 2005,
[   1.0000000]     2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 
2015, 2016, 2017,
[   1.0000000]     2018, 2019 The NetBSD Foundation, Inc.  All rights 
reserved.
[   1.0000000] Copyright (c) 1982, 1986, 1989, 1991, 1993
[   1.0000000]     The Regents of the University of California.  All 
rights reserved.
[   1.0000000] NetBSD 8.99.34 (GENERIC) #0: Sun Feb 24 08:02:45 UTC 2019
[   1.0000000] 
[email protected]:/usr/src/sys/arch/mac68k/compile/GENERIC
[   1.0000000] Apple Macintosh LC 475/33  (68040)
[   1.0000000] cpu: delay factor 1051
[   1.0000000] fpu: mc68040
[   1.0000000] total memory = 132 MB
[   1.0000000] avail memory = 124 MB
[   1.0000000] mrg: 'Quadra/Centris 605 ROMs' ROM glue, tracing off, debug 
off, silent traps
[   1.0000000] mainbus0 (root)
[   1.0000000] obio0 at mainbus0
[   1.0000000] esp0 at obio0 addr 0 (quick): address 0x42b000: NCR53C96, 
16MHz, SCSI ID 7
[   1.0000000] scsibus0 at esp0: 8 targets, 8 luns per target
[   1.0000000] adb0 at obio0
[   1.0000000] asc0 at obio0: Apple Sound Chip
[   1.0000000] intvid0 at obio0 @ f9001000: DAFB video subsystem, monitor 
sense 1
[   1.0000000] intvid0: 640 x 480, monochrome
[   1.0000000] macfb0 at intvid0
[   1.0000000] wsdisplay0 at macfb0 (kbdmux ignored)
[   1.0000000] iwm0 at obio0: Apple GCR floppy disk controller
[   1.0000000] fd0 at iwm0 drive 0: (HD disk -- not supported)
[   1.0000000] fd1 at iwm0 drive 1: (HD disk -- not supported)
[   1.0000000] zsc0 at obio0 chip type 0
[   1.0000000] zsc0 channel 0: d_speed   9600 DCD clk 0 CTS clk 0
[   1.0000000] zstty0 at zsc0 channel 0 (console i/o)
[   1.0000000] zsc0 channel 1: d_speed   9600 DCD clk 0 CTS clk 0
[   1.0000000] zstty1 at zsc0 channel 1
[   1.0000000] nubus0 at mainbus0
[   1.0000000] sn0 at nubus0 slot e: Macintosh LC Ethernet Adapter
[   1.0000000] sn0: Ethernet address 00:01:98:34:0a:af
[   1.0070344] scsibus0: waiting 2 seconds for devices to settle...
[   1.0813425] adb0 (direct, Cuda): 2 targets
[   1.1974730] aed0 at adb0 addr 0: ADB Event device
[   1.2548707] akbd0 at adb0 addr 2: keyboard II
[   1.3069412] wskbd0 at akbd0 (mux ignored)
[   1.3548783] ams0 at adb0 addr 3: EMP mouse <ALP3> 3-button, 480 dpi
[   1.4558255] wsmouse0 at ams0 (mux ignored)
[   3.2026086] sd0 at scsibus0 target 0 lun 0: <SCSI, PCCARD Flash, 1.28> 
disk removable
[   3.3027567] sd0: 61064 MB, 16383 cyl, 15 head, 63 sec, 512 bytes/sect x 
125059072 sectors
[   3.4035060] sd1 at scsibus0 target 0 lun 1: <SCSI, Compact Flash, 1.28> 
disk removable
[   3.5038328] sd1: drive offline
[   3.5399414] sd2 at scsibus0 target 0 lun 2: <SCSI, SmartMedia, 1.28> 
disk removable
[   3.6369543] sd2: drive offline
[   3.6729607] sd3 at scsibus0 target 0 lun 3: <SCSI, Secure Digital, 
1.28> disk removable
[   3.7720454] sd3: 61056 MB, 15506 cyl, 128 head, 63 sec, 512 bytes/sect 
x 125042688 sectors
[   3.8770380] sd4 at scsibus0 target 0 lun 4: <SCSI, Memory Stick, 1.28> 
disk removable
[   3.9741249] sd4: drive offline
[   4.0117232] sd0: async, 8-bit transfers
[   4.0117232] sd1: async, 8-bit transfers
[   4.0117232] sd2: async, 8-bit transfers
[   4.0117232] sd3: async, 8-bit transfers
[   4.0117232] sd4: async, 8-bit transfers
[   4.7688770] swwdog0: software watchdog initialized
[   4.8369274] WARNING: 1 error while detecting hardware; check system 
log.
[   4.9171894] boot device: sd0
[   4.9689727] root on sd0a dumps on sd0b
[   5.0856203] root file system type: ffs
[   5.1405822] kern.module.path=/stand/mac68k/8.99.34/modules
[   5.2356266] panic: Unexpected phase in transfer_pdma.
[   5.2356266] cpu0: Begin traceback...
[   5.2356266] ?(?)
[   5.2356266] db_panic(0,9ac000,0,32d680,3f0e6c) at 0
[   5.2356266] vpanic(28b942,3f0e78,3f0ebc,15bae,28b942) + 154
[   5.2356266] panic(28b942,4d8983c,ea9c3000,0,0) + c
[   5.2356266] transfer_pdma(?)
[   5.2356266] mi_switch(32d680) + 140
[   5.2356266] 
sleepq_block(0,0,349b9c,32d680,349b90,2b98b4,32d2e4,9ac09c,9ac558) + 16c
[   5.2356266] cv_wait(349b90,349b9c) + 78
[   5.2356266] kthread_join(acd620) + 72
[   5.2356266] config_finalize_mountroot(0,0,5,e00006b,3f0fa4) + 24
[   5.2356266] main(1cc4ba,796000,0,1000,187c06) + 71a
[   5.2356266] ?() at 419
[   5.2356266] cpu0: End traceback...
Stopped in pid 0.1 (system) at  netbsd:cpu_Debugger+0x6:        unlk    a6