initialize bools

[kpedro88]

A crash was found in Phase2 production using 9_3_6:
https://cms-unified.web.cern.ch/cms-unified//joblogs/pdmvserv_task_TSG-PhaseIITDRFall17GS-00009__v1_T_180403_202250_828/139/TSG-PhaseIITDRFall17GS-00009_0/c0eb431e-3776-11e8-a946-02163e01877e-52-3-logArchive/job/WMTaskSpace/cmsRun1/cmsRun1-stdout.log

I recompiled pythia8 and dependent packages with debug symbols, which produced the following information when run:

Thread 7 "cmsRun" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffd2d7e700 (LWP 58729)]
0x00007fffddfdbef4 in Pythia8::TimeShower::pT2nextQED (this=0x7fffd5842700, pT2begDip=0.20562544615866121, pT2sel=0, dip=..., event=...) at src/TimeShower.cc:2415
2415        if (canEnhanceET) emitCoefTot *= userHooksPtr->enhanceFactor("fsr:Q2QA");
(gdb) backtrace
#0  0x00007fffddfdbef4 in Pythia8::TimeShower::pT2nextQED (this=0x7fffd5842700, pT2begDip=0.20562544615866121, pT2sel=0, dip=..., event=...) at src/TimeShower.cc:2415
#1  0x00007fffddfcfcb2 in Pythia8::TimeShower::showerQED (this=0x7fffd5842700, i1=112, i2=113, event=..., pTmax=1.0187130221146139) at src/TimeShower.cc:446
#2  0x00007fffde144289 in Pythia8::ParticleDecays::decay (this=0x7fffba27c428, iDec=48, event=...) at src/ParticleDecays.cc:330
#3  0x00007fffde06718b in Pythia8::HadronLevel::next (this=0x7fffba27bd00, event=...) at src/HadronLevel.cc:262
#4  0x00007fffddeb9e9d in Pythia8::Pythia::forceHadronLevel (this=0x7fffba240000, findJunctions=true) at src/Pythia.cc:2014
#5  0x00007fffddeb7e35 in Pythia8::Pythia::next (this=0x7fffba240000) at src/Pythia.cc:1659
#6  0x00007fffde4758b1 in gen::Py8PtGun::generatePartonsAndHadronize (this=this@entry=0x7fffe14cd858) at /uscms_data/d3/pedrok/phase2/test/CMSSW_9_3_6/src/GeneratorInterface/Pythia8Interface/plugins/Py8PtGun.cc:108
#7  0x00007fffde47a4b0 in edm::GeneratorFilter<gen::Py8PtGun, gen::ExternalDecayDriver>::filter (this=0x7fffe14cd800, ev=...) at /cvmfs/cms.cern.ch/slc6_amd64_gcc630/cms/cmssw/CMSSW_9_3_6/src/GeneratorInterface/Core/interface/GeneratorFilter.h:150
...
(gdb) frame 0
#0  0x00007fffddfdbef4 in Pythia8::TimeShower::pT2nextQED (this=0x7fffd5842700, pT2begDip=0.20562544615866121, pT2sel=0, dip=..., event=...) at src/TimeShower.cc:2415
2415        if (canEnhanceET) emitCoefTot *= userHooksPtr->enhanceFactor("fsr:Q2QA");
(gdb) print canEnhanceET
$1 = 63
(gdb) print emitCoefTot
$2 = 0.064956651662100753
(gdb) print userHooksPtr
$3 = (Pythia8::UserHooks *) 0x0
(gdb) ptype canEnhanceET
type = bool
(gdb) print canEnhanceTrial
$4 = false
(gdb) print canEnhanceEmission
$5 = false
(gdb) print canEnhanceET
$6 = 63
(gdb) print doTrialNow
$7 = 32

The member bools canEnhanceET and doTrialNow do not have boolean values because they are not initialized properly. pT2nextQED() can be called by either pTnext() or showerQED(). The former initializes these bools, the latter does not (and the latter appears in the stack trace above).

The crash no longer occurs with the fix in this PR.

[cmsbuild]

A new Pull Request was created by @kpedro88 (Kevin Pedro) for branch cms/230.

@cmsbuild, @smuzaffar, @gudrutis, @mrodozov can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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external issue cms-sw/cmsdist#3930

[kpedro88]

@smuzaffar we'll need to backport this to 9_3_X

[smuzaffar]

done:
10.2.X: cms-sw/cmsdist#3931
9.3.X: cms-sw/cmsdist#3932

[alberto-sanchez]

@smuzaffar Can this be propagated to 7.1.X, which currently uses 8.226, but suffers from the same problem. I am seeing same crash, when using the pguns.

[kpedro88]

@alberto-sanchez I created a backport PR, see #11

[alberto-sanchez]

@kpedro88 Thanks a lot!