yum is always locked by something else

I cant run yum on some of my servers, it is always being used by something else.

I have loads of these

root 27835 0.0 0.0 3100 2244 ? S 16:21 0:00 sh -c yum list-sec 2>/dev/null 2>/dev/null root 27836 18.5 1.9 86040 80056 ? S 16:21 0:01 /usr/bin/python /usr/bin/yum list-sec root 27837 0.0 0.0 3100 2248 ? S 16:21 0:00 sh -c yum list-sec 2>/dev/null 2>/dev/null root 27838 2.8 0.5 26648 20424 ? S 16:21 0:00 /usr/bin/python /usr/bin/yum list-sec root 27847 7.3 0.5 28872 21068 pts/0 T 16:21 0:00 /usr/bin/python /usr/bin/yum -y update Then when I kill them all sometimes I can run yum, but sometimes they all start again. Its always the same few servers I have. Any ideas?

Thanks