K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2017-02-25T10:38:18.161854Z
K 7
svn:log
V 644
Do not leak mount references for dying threads.

Thread might create a condition for delayed SU cleanup, which creates
a reference to the mount point in td_su, but exit without returning
through userret(), e.g. when terminating due to single-threading or
process exit.  In this case, td_su reference is not dropped and mount
point cannot be freed.

Handle the situation by clearing td_su also in the thread destructor
and in exit1().  softdep_ast_cleanup() has to receive the thread as
argument, since e.g. thread destructor is executed in different
context.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks

END