Prevent cv_waiters wraparound.

r282971 attempted to fix this problem by decrementing cv_waiters after
waking up from sleeping on a condition variable, but this can result in
a use-after-free if the CV is freed before all woken threads have had a
chance to run. Instead, avoid incrementing cv_waiters past INT_MAX, and
have cv_signal() explicitly check for sleeping threads once cv_waiters has
reached this bound.

Reviewed by:	jhb
MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D4822

0 files changed, 0 insertions, 0 deletions