Please help reviewing ! Got another crash because of the ttymodem() / ttyclose() race

[Martin Blapp]

Hi all,

This time its FreeBSD 5.5 RELEASE. Same code is in 6.X (which crashed on a 
different server 5 days ago) and CURRENT.

#25 0xc064f4bd in ttymodem ()
#26 0xc06532bd in ptcclose ()
#27 0xc05e4e14 in spec_close ()
#28 0xc05e3edf in spec_vnoperate ()
#29 0xc06815e0 in vn_close ()
#30 0xc06825f2 in vn_closefile ()
#31 0xc0601ba4 in fdrop_locked ()
#32 0xc0601af1 in fdrop ()
#33 0xc060015b in closef ()
#34 0xc05fd5e5 in close ()
#35 0xc07c5e97 in syscall ()

Can PLEASE PLEASE someone help me fix this problem
and review the patch ?

The patch is based on Max Laiers tty.t_pgrp patch.

http://mx.imp.ch/patch-tty.t_pgrp.diff

Especially the part in ttyinfo() needs to be reviewed
carefully.

Martin

Martin Blapp, <mb at imp.ch> <mbr at FreeBSD.org>
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