recent current panic: ic: bio_offset 0 wrong, should be 16844800

Recent i386 CURRENT panic at boot diskless PC:
....
Mounting root from nfs:
NFS ROOT: 1.1.1.1:/i386/netboot
Interface fxp0 IP-Address 1.1.1.2 Broadcast 1.1.1.255
Loading configuration files.
Entropy harvesting: interrupts ethernet point_to_point.
Starting file system checks:
cp: utmp: Read-only file system
/etc/rc.d/cleanvar: cannot create /var/run/clean_var: Read-only file system
+++ mount_md of /var
+++ populate /var using /etc/mtree/BSD.var.dist
+++ create log files based on the contents of /etc/newsyslog.conf
+++ create lastlog
ic: bio_offset 0 wrong, should be 16844800
Debugger("panic")
Stopped at      Debugger+0x54:  xchgl   %ebx,in_Debugger.0
db> tr
Debugger(c083a924,c08fc1c0,c084129f,d628b774,100) at Debugger+0x54
panic(c084129f,0,0,1010800,0) at panic+0xd5
dev_strategy(c79f59e0,0,8100,d628b7b0,c0614d68) at dev_strategy+0xb8
spec_freeblks(d628b808,d628b834,c0751488,d628b808,0) at spec_freeblks+0xb2
spec_vnoperate(d628b808,0,1008,0,2b3) at spec_vnoperate+0x18
ffs_blkfree(c2c46000,c2d9d618,2021,0,800) at ffs_blkfree+0x1e8
handle_workitem_freeblocks(c2d7a400,0,0,d628b918,0) at
handle_workitem_freeblock
s+0x328
softdep_setup_freeblocks(c2dd4230,0,0,800,c79f59e0) at
softdep_setup_freeblocks+
0x8a3
ffs_truncate(c2dfee38,0,0,0,c1672d00) at ffs_truncate+0x6ff
handle_workitem_remove(c2ca7ee0,0,c2dd4230,1,d628bb8c) at
handle_workitem_remove
+0x1ab
softdep_setup_remove(c79f4388,c2dd4ec4,c2dd4230,1,d628bbb4) at
softdep_setup_rem
ove+0xcc
ufs_dirremove(c2de0e38,c2dd4230,800c,1,d628bbc0) at ufs_dirremove+0x16d
ufs_rmdir(d628bc20,d628bccc,c06b4424,d628bc20,d628bc1c) at ufs_rmdir+0xef
ufs_vnoperate(d628bc20,d628bc1c,2,c2ca6400,c08d2400) at ufs_vnoperate+0x18
kern_rmdir(c2c8ba00,bfbfef56,0,d628bd40,c07d0bb0) at kern_rmdir+0x1b4
rmdir(c2c8ba00,d628bd10,c0855704,3ee,1) at rmdir+0x22
syscall(2f,2f,2f,0,0) at syscall+0x2c0
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (137, FreeBSD ELF32, rmdir), eip = 0x280bd1af, esp = 0xbfbfee7c,
ebp
 = 0xbfbfee98 ---
db>

Thanks!