Unkillable KSE threaded proc

[Andrew Gallatin]

Andrew Gallatin writes:
 > 
 > If I send a kill -9 to a threaded process in a creative way, I see it
 > get stuck forever exiting.  (run from a /bin/sh script,
 > killed via ssh $MACHINE skill -9 -u gallatin)
 > 
 > It shows up in a ddb ps like this:
 > 
 > 3403 c1652540 e52fe000 1387     1  3401 000c402 (threaded) mx_pingpong
 >    thread 0xc2de4c60 ksegrp 0xc15b2200 [SUSP]
 > 


FWIW, before sending it an skill -9, another run of the same program
will show up in ddb ps like this:

3514 c1b65540 e6842000    0  3058  3514 000c002 (threaded) mx_pingpong
   thread 0xc2e0ab00 ksegrp 0xc1b60100 [SLPQ kserel 0xc1b6015c][SLP]
   thread 0xc1af7840 ksegrp 0xc1b60100 [CPU 1][kse 0xc1af8c00]
   thread 0xc2de5840 ksegrp 0xc1b60100 [SLPQ mx cv 0xc16b9e40][SLP]
   thread 0xc2de56e0 ksegrp 0xc2de3800 [SLPQ ksesigwait 0xc1b65640][SLP]


Since there's only one thread left in the hung case, could it just
be some sort of race in the exit code?

Thanks,

Drew