I have a multi job job say 'A', 'A' defines three phases,

Phase 1 - Run job 'B'
Phase 2 - Run job 'C','D','E'
Phase 3 - Run job 'F' - clean up job
I am facing a problem wherein when 'B' runs, it sometime times blocks if 'A' comes back in build queue (due to scm change). So this becomes a deadlock for me, 'A' build 1 runs which builds 'B' build 1. However, 'A' build 2 comes in pipeline (due to scm change or upstream project change). 'B' waits endlessly since 'A' build 2 is in waiting queue.

'A' build 1 ----- waits for --> 'B' build 1 ------- blocked by -------> 'A' build 2 in build queue

Similar issue reported earlier by different user is
https://groups.google.com/forum/#!topic/jenkinsci-users/jkFWsiw6V0c

And

Please help.

Thanks