When one repeatedly launches gstreamer using h264 vpudec and then terminating it with killall it leads to situation where pipeline stops working. From log below it looks like that it doesn't properly free decoder and they run out. I couldn't replicate this behaviour by using gst-launch -e and properly termination it with ctrl-c sending EOS.
gst-launch-1.0: ../../source/h264high/h264hwd_asic.c:1009: H264RunAsic: Assertio
n `0' failed.
test: line 10: 5842 Aborted (core dumped) gst-launch-1.0 -e -v
$START vpudec ! textoverlay text="blabla" ! $SINK
[ 505.839740] audit: type=1701 audit(1520332016.986:12): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=5284 comm="rtpjitterbuffer" exe="/usr/bin/gst-launch-1.0" sig=6
[ 510.376891] hantrodec: DEC still enabled -> reset
[ 510.417429] hantrodec: DEC still enabled -> reset
[ 510.435842] hantrodec: DEC still enabled -> reset
As side note how one builds h264 encoder? It could lead to easier example of videotestsrc ! encode h264 ! vpudec ! glimagesink
test scripts are
gst-launch-1.0 ...(rtsp h264 stream from camera) ! vpudec ! glimagesink
for ì in `seq 1 100`; do
sh test &