Hi all, I encountered the following error when I run the attached MPI RMA code (simplified to reproduce the error) with two nodes. The code works well on a single node (with multiple processes and multiple threads), and had no problem with a single thread per process on two nodes. I used the current MPICH master branch, built it with default configure options, and executed on a linux cluster (MCS Breadboard node 70 and 71, Ubuntu 12.04.4, gcc 4.6.3). $ mpiexec -f hosts_pthread -n 2 ./rma_get_pthread 4 num_threads: 4 Assertion failed in file src/mpid/ch3/src/ch3u_rma_sync.c at line 5979: MPIU_Object_get_ref(((curr_ptr->request))) >= 0 internal ABORT - process 1 =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = PID 22979 RUNNING AT bb71 = EXIT CODE: 1 = CLEANING UP REMAINING PROCESSES = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES =================================================================================== [proxy:0:0@bb70] HYD_pmcd_pmip_control_cmd_cb (pm/pmiserv/pmip_cb.c:885): assert (!closed) failed [proxy:0:0@bb70] HYDT_dmxu_poll_wait_for_event (tools/demux/demux_poll.c:76): callback returned error status [proxy:0:0@bb70] main (pm/pmiserv/pmip.c:206): demux engine error waiting for event [mpiexec@bb70] HYDT_bscu_wait_for_completion (tools/bootstrap/utils/bscu_wait.c:76): one of the processes terminated badly; aborting [mpiexec@bb70] HYDT_bsci_wait_for_completion (tools/bootstrap/src/bsci_wait.c:23): launcher returned error waiting for completion [mpiexec@bb70] HYD_pmci_wait_for_completion (pm/pmiserv/pmiserv_pmci.c:218): launcher returned error waiting for completion [mpiexec@bb70] main (ui/mpich/mpiexec.c:344): process manager error waiting for completion Could someone take a look at it and tell me what I did wrong or whether it is a bug in MPICH? Thank you, Sangmin