panic: Assertion !(curthread->td_flags & TDF_SINTR) failed

Hi!

With my CURRENT installation from Apr 1, I get:

panic: Assertion !(curthread->td_flags & TDF_SINTR) failed at /usr/src/sys/kern/subr_sleepqueue.c:529
cpuid = 0
KDB: enter: panic

[...]

#11 0xc066a32b in panic (fmt=0xc08a525c "Assertion %s failed at %s:%d") at /usr/src/sys/kern/kern_shutdown.c:542
#12 0xc068aadc in sleepq_wait (wchan=0xc1c163a8) at /usr/src/sys/kern/subr_sleepqueue.c:529
#13 0xc0670725 in msleep (ident=0xc1c163a8, mtx=0xc1c1629c, priority=92, wmesg=0xc08ae466 "stopevent", timo=0)
    at /usr/src/sys/kern/kern_synch.c:209
#14 0xc06966f8 in stopevent (p=0xc1c16234, event=2, val=2) at /usr/src/sys/kern/sys_process.c:1028
#15 0xc066e034 in issignal (td=0xc18e2bd0) at /usr/src/sys/kern/kern_sig.c:2544
#16 0xc066aed7 in cursig (td=0xc18e2bd0) at signalvar.h:265
#17 0xc068a732 in sleepq_catch_signals (wchan=0xc1750c10) at /usr/src/sys/kern/subr_sleepqueue.c:377
#18 0xc068ab22 in sleepq_wait_sig (wchan=0xc1750c10) at /usr/src/sys/kern/subr_sleepqueue.c:545
#19 0xc0670716 in msleep (ident=0xc1750c10, mtx=0x0, priority=345, wmesg=0xc08afc24 "ttyin", timo=0)
    at /usr/src/sys/kern/kern_synch.c:207
#20 0xc069e945 in ttysleep (tp=0xc1750c00, chan=0xc1750c10, pri=345, wmesg=0xc08afc24 "ttyin", timo=0)
    at /usr/src/sys/kern/tty.c:2762
#21 0xc069d4e3 in ttread (tp=0xc1750c00, uio=0xc62eec64, flag=0) at /usr/src/sys/kern/tty.c:1864
#22 0xc069f4c7 in ttyread (dev=0xc1746200, uio=0xc62eec64, flag=0) at linedisc.h:100
#23 0xc080ec16 in scread (dev=0xc1746200, uio=0xc62eec64, flag=0) at /usr/src/sys/dev/syscons/syscons.c:596
#24 0xc06446c1 in giant_read (dev=0xc1746200, uio=0xc62eec64, ioflag=0) at /usr/src/sys/kern/kern_conf.c:300
#25 0xc061fc8e in devfs_read_f (fp=0xc17f70d8, uio=0xc62eec64, cred=0xc1c39480, flags=0, td=0xc18e2bd0)
    at /usr/src/sys/fs/devfs/devfs_vnops.c:773
#26 0xc0691145 in dofileread (td=0xc18e2bd0, fd=0, fp=0xc17f70d8, auio=0xc62eec64, offset=Unhandled dwarf expression opcode 0x93

) at file.h:235
#27 0xc0690fda in kern_readv (td=0xc18e2bd0, fd=0, auio=0xc62eec64) at /usr/src/sys/kern/sys_generic.c:192
#28 0xc0690f05 in read (td=0xc18e2bd0, uap=0xc1033000) at /usr/src/sys/kern/sys_generic.c:116
#29 0xc0830436 in syscall (frame=
      {tf_fs = 59, tf_es = 59, tf_ds = 59, tf_edi = 1, tf_esi = 1, tf_ebp = -1077941016, tf_isp = -970003100, tf_ebx = 0, tf_edx
 = 0, tf_ecx = 0, tf_eax = 3, tf_trapno = 12, tf_err = 2, tf_eip = 672429263, tf_cs = 51, tf_eflags = 518, tf_esp = -1077941300,
 tf_ss = 59}) at /usr/src/sys/i386/i386/trap.c:1016
#30 0xc081c11f in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:190
#31 0x00000033 in ?? ()

by running the command

  strace -e read,write cat

and then interrupting it with Ctrl-C (of course, procfs is mounted and the
devel/strace is installed before doing this).

Regards,
Csaba