dlopen1 failing on CentOS 7 (and others?)

[karya0]

Checkpoint dlopen1 hangs with the following backtrace for main thread and the ckpt thread:

(gdb) bt
#0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x00007fe1e3c33d4d in _L_lock_840 () from /lib64/libpthread.so.0
#2  0x00007fe1e3c33c6a in __GI___pthread_mutex_lock (mutex=0x7fe1e5352908 <_rtld_local+2312>)
    at pthread_mutex_lock.c:85
#3  0x00007fe1e4208189 in __dlsym (handle=<optimized out>, name=<optimized out>) at dlsym.c:68
#4  0x00007fe1e4afca25 in dmtcp::FileConnList::prepareShmList (this=this@entry=0x7fe1e534a208)
    at file/fileconnlist.cpp:151
#5  0x00007fe1e4afcdc9 in dmtcp::FileConnList::preLockSaveOptions (this=0x7fe1e534a208)
    at file/fileconnlist.cpp:75
#6  0x00007fe1e4ad5766 in dmtcp::ConnectionList::eventHook (this=0x7fe1e534a208, event=128, 
    event@entry=DMTCP_EVENT_THREADS_SUSPEND, data=data@entry=0x0) at connectionlist.cpp:118
#7  0x00007fe1e4afc2b3 in dmtcp_FileConnList_EventHook (event=event@entry=DMTCP_EVENT_THREADS_SUSPEND, 
    data=data@entry=0x0) at file/fileconnlist.cpp:46
#8  0x00007fe1e4acd54a in dmtcp_event_hook (event=DMTCP_EVENT_THREADS_SUSPEND, data=0x0) at ipc.cpp:46
#9  0x00007fe1e463bc88 in dmtcp::DmtcpWorker::waitForStage2Checkpoint () at dmtcpworker.cpp:550
#10 0x00007fe1e464b3a2 in dmtcp::callbackPreCheckpoint () at mtcpinterface.cpp:79
#11 0x00007fe1e465720c in checkpointhread (dummy=<optimized out>) at threadlist.cpp:358
#12 0x00007fe1e464dafc in pthread_start (arg=<optimized out>) at threadwrappers.cpp:159
#13 0x00007fe1e3c31df5 in start_thread (arg=0x7fe1e25cd700) at pthread_create.c:308
#14 0x00007fe1e464d959 in clone_start (arg=0x7fe1e532f808) at threadwrappers.cpp:68
#15 0x00007fe1e3f3c1ad in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
(gdb) 
#0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x00007fe1e3c33d4d in _L_lock_840 () from /lib64/libpthread.so.0
#2  0x00007fe1e3c33c6a in __GI___pthread_mutex_lock (mutex=0x7fe1e5352908 <_rtld_local+2312>)
    at pthread_mutex_lock.c:85
#3  0x00007fe1e4208189 in __dlsym (handle=<optimized out>, name=<optimized out>) at dlsym.c:68
#4  0x00007fe1e4afca25 in dmtcp::FileConnList::prepareShmList (this=this@entry=0x7fe1e534a208)
    at file/fileconnlist.cpp:151
#5  0x00007fe1e4afcdc9 in dmtcp::FileConnList::preLockSaveOptions (this=0x7fe1e534a208)
    at file/fileconnlist.cpp:75
#6  0x00007fe1e4ad5766 in dmtcp::ConnectionList::eventHook (this=0x7fe1e534a208, event=128, 
    event@entry=DMTCP_EVENT_THREADS_SUSPEND, data=data@entry=0x0) at connectionlist.cpp:118
#7  0x00007fe1e4afc2b3 in dmtcp_FileConnList_EventHook (event=event@entry=DMTCP_EVENT_THREADS_SUSPEND, 
    data=data@entry=0x0) at file/fileconnlist.cpp:46
#8  0x00007fe1e4acd54a in dmtcp_event_hook (event=DMTCP_EVENT_THREADS_SUSPEND, data=0x0) at ipc.cpp:46
#9  0x00007fe1e463bc88 in dmtcp::DmtcpWorker::waitForStage2Checkpoint () at dmtcpworker.cpp:550
#10 0x00007fe1e464b3a2 in dmtcp::callbackPreCheckpoint () at mtcpinterface.cpp:79
#11 0x00007fe1e465720c in checkpointhread (dummy=<optimized out>) at threadlist.cpp:358
#12 0x00007fe1e464dafc in pthread_start (arg=<optimized out>) at threadwrappers.cpp:159
#13 0x00007fe1e3c31df5 in start_thread (arg=0x7fe1e25cd700) at pthread_create.c:308
#14 0x00007fe1e464d959 in clone_start (arg=0x7fe1e532f808) at threadwrappers.cpp:68
#15 0x00007fe1e3f3c1ad in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

As can be seen, the main thread got suspended while in the middle of dlsym() and thus when ckpt thread tried to call dlsym(), it reached a deadlock. We should enable the dlsym wrapper and use WRAPPER_EXECUTION_LOCK inside it.