Should syncache.count ever be negative?

[Matt Reimer]

On a eight core machine running RELENG_7 I'm seeing TCP stalls,
sometimes lasting up to 60 seconds or so. While trying to track this
down I noticed that net.inet.tcp.syncache.count is negative. Should it
be possible for the count to go negative? Perhaps it indicates a race,
or the counter is wrongly being decremented twice?

Matt

# sysctl net.inet.tcp.syncache
net.inet.tcp.syncache.rst_on_sock_fail: 1
net.inet.tcp.syncache.rexmtlimit: 3
net.inet.tcp.syncache.hashsize: 512
net.inet.tcp.syncache.count: -97
net.inet.tcp.syncache.cachelimit: 15360
net.inet.tcp.syncache.bucketlimit: 30