Segfault on ccb_explore_adf -cb_type dr

[NegatioN]

Describe the bug

When training a model, and later running it in test-mode, somehow a segfault is produced.

./vw --ccb_explore_adf -q UA --all_slots_loss --cb_type dr -f trained.model -d ${PROVIDED_EXAMPLE_FILE} && ./vw --ccb_explore_adf -q UA --all_slots_loss --cb_type dr -i trained.model -t -d  ${PROVIDED_EXAMPLE_FILE}

Output from debug build:

creating quadratic features for pairs: UA
final_regressor = trained.model
using no cache
Reading datafile = /home/AUSER/test/vowpal_data/obe2.dat
num sources = 1
Num weight bits = 18
learning rate = 0.5
initial_t = 0
power_t = 0.5
cb_type = dr
Enabled learners: gd, generate_interactions, scorer-identity, csoaa_ldf-rank, cb_adf, cb_explore_adf_greedy, cb_sample, shared_feature_merger, ccb_explore_adf
Input label = CCB
Output pred = DECISION_PROBS
average  since         example        example        current        current  current
loss     last          counter         weight          label        predict features
-0.16661 -0.16661            1            1.0   7:0,28:0,... 7,28,21,25,...     3120

finished run
number of examples = 1
weighted example sum = 1.000000
weighted label sum = 0.000000
average loss = -0.166610
total feature number = 3120
[warning] model file has set of {-q, --cubic, --interactions} settings stored, but they'll be OVERRIDDEN by set of {-q, --cubic, --interactions} settings from command line.
creating quadratic features for pairs: UA
only testing
using no cache
Reading datafile = /home/AUSER/test/vowpal_data/obe2.dat
num sources = 1
Num weight bits = 18
learning rate = 0.5
initial_t = 1
power_t = 0.5
cb_type = dr
Enabled learners: gd, generate_interactions, scorer-identity, csoaa_ldf-rank, cb_adf, cb_explore_adf_greedy, cb_sample, shared_feature_merger, ccb_explore_adf
Input label = CCB
Output pred = DECISION_PROBS
average  since         example        example        current        current  current
loss     last          counter         weight          label        predict features
vw: /home/AUSER/github/vowpal_wabbit/vowpalwabbit/core/include/vw/core/v_array.h:121: T& VW::v_array<T, typename std::enable_if<std::is_trivially_copyable<_Tp>::value>::type>::operator[](size_t) const [with T = VW::action_score; typename std::enable_if<std::is_trivially_copyable<_Tp>::value>::type = void; size_t = long unsigned int]: Assertion `i < size()' failed.
[1]    189477 IOT instruction (core dumped)  ./vw --ccb_explore_adf -q UA --all_slots_loss --cb_type dr -i trained.model -

I expect an example of data that is trainable, to also be testable, without segfaulting.

How to reproduce

PROVIDED_EXAMPLE_FILE:

ccb shared |User userID='aUser'
ccb action |Action contentId='a'
ccb action |Action contentId='b'
ccb action |Action contentId='c'
ccb action |Action contentId='d'
ccb action |Action contentId='e'
ccb action |Action contentId='f'
ccb action |Action contentId='g'
ccb action |Action contentId='h'
ccb action |Action contentId='i'
ccb action |Action contentId='j'
ccb action |Action contentId='k'
ccb action |Action contentId='l'
ccb action |Action contentId='m'
ccb action |Action contentId='n'
ccb action |Action contentId='o'
ccb action |Action contentId='p'
ccb action |Action contentId='q'
ccb action |Action contentId='r'
ccb action |Action contentId='s'
ccb action |Action contentId='t'
ccb action |Action contentId='x'
ccb action |Action contentId='y'
ccb action |Action contentId='z'
ccb action |Action contentId='aa'
ccb action |Action contentId='ab'
ccb action |Action contentId='ac'
ccb action |Action contentId='ad'
ccb action |Action contentId='ae'
ccb action |Action contentId='af'
ccb action |Action contentId='ag'
ccb slot 7:0:0.2814157009124756,18:0.4986087679862976,0:0.09111946821212769,13:0.034919969737529755,17:0.022231325507164,24:0.021717887371778488,12:0.02091880328953266,22:0.008943566121160984,21:0.0035167494788765907,4:0.003486328525468707,8:0.00306233623996377,14:0.002975673880428076,25:0.002446186961606145,11:0.0013868052046746016,6:0.0007644615834578872,23:0.0007121390081010759,10:0.0006081887986510992,20:0.00046663329703733325,29:0.00024663639487698674,5:0.00020450385636650026,19:6.42634549876675e-05,15:6.378938996931538e-05,9:4.367829387774691e-05,27:2.616703204694204e-05,1:1.8396624000160955e-05,2:1.1368916602805257e-05,26:9.699509064375889e-06,16:5.553145911108004e-06,28:2.4986536573123885e-06,3:2.245711812065565e-06 7,18,0,13,17,24,12,22,21,4,8,14,25,11,6,23,10,20,29,5,19,15,9,27,1,2,26,16,28,3 |
ccb slot 28:0:0.38746780157089233,12:0.4452095031738281,17:0.11129308491945267,13:0.021261485293507576,2:0.010781776160001755,5:0.006623556837439537,14:0.006618801970034838,0:0.00422333087772131,3:0.0029810182750225067,25:0.0011069459142163396,22:0.0010891001438722014,21:0.00043250489397905767,20:0.00032753165578469634,29:0.0002478094829712063,24:0.0001928548444993794,18:3.78785262000747e-05,1:2.8776834369637072e-05,8:2.2285950763034634e-05,10:1.975510713236872e-05,19:1.1510705917316955e-05,15:1.0838572052307427e-05,4:4.2137894524785224e-06,11:2.6999800866178703e-06,16:1.461011038372817e-06,6:1.387319798595854e-06,27:1.0769275604616269e-06,23:9.243367458111607e-07,9:1.2605019605871348e-07,26:6.900691684741389e-10 28,12,17,13,2,5,14,0,3,25,22,21,20,29,24,18,1,8,10,19,15,4,11,16,6,27,23,9,26 |
ccb slot 21:0:0.009457200765609741,17:0.13830232620239258,20:0.06671705096960068,18:0.060711901634931564,13:0.04832380264997482,12:0.02896728552877903,15:0.027813201770186424,1:0.01238782238215208,5:0.5844042301177979,24:0.007916729897260666,22:0.005313423927873373,3:0.0030796348582953215,8:0.0026463039685040712,2:0.001610504579730332,4:0.0004394367279019207,14:0.0003743874840438366,11:0.0003052169340662658,9:0.0002891358162742108,10:0.0002627648937050253,0:0.0002489395847078413,25:0.00015549163799732924,29:0.00012897276610601693,23:7.323167665163055e-05,6:4.6114979340927675e-05,16:1.574967973283492e-05,27:4.545572664937936e-06,26:4.3639242903736886e-06,19:9.780344356613568e-08 21,17,20,18,13,12,15,1,5,24,22,3,8,2,4,14,11,9,10,0,25,29,23,6,16,27,26,19 |
ccb slot 25:0:0.04852084442973137,4:0.18842479586601257,0:0.11689016968011856,11:0.09394704550504684,15:0.07111208140850067,14:0.06413374841213226,1:0.2144840508699417,17:0.04394223168492317,22:0.04030191898345947,6:0.025946179404854774,20:0.02485107257962227,23:0.02306993119418621,8:0.01103772409260273,18:0.009649633429944515,24:0.0051767947152256966,3:0.004639864899218082,5:0.0036481451243162155,13:0.003012213623151183,27:0.0018589160172268748,2:0.0014349337434396148,12:0.0013534734025597572,16:0.0009505416383035481,26:0.0006534871645271778,19:0.0006136561860330403,29:0.00025192913017235696,9:4.8225138016277924e-05,10:4.6369124902412295e-05 25,4,0,11,15,14,1,17,22,6,20,23,8,18,24,3,5,13,27,2,12,16,26,19,29,9,10 |
ccb slot 22:-1:0.2308475524187088,29:0.7056121826171875,24:0.024420326575636864,13:0.017714975401759148,5:0.006036168430000544,15:0.004493136424571276,17:0.002671352354809642,14:0.0016715804813429713,18:0.001555807190015912,12:0.0014371434226632118,19:0.0010492069413885474,10:0.0006786655867472291,0:0.0003868465428240597,2:0.0003725361602846533,3:0.0003565707884263247,4:0.00022809540678281337,6:0.00016483885701745749,11:0.00013846883666701615,1:3.974044739152305e-05,16:3.603336153901182e-05,8:3.055339402635582e-05,27:1.7396419934812002e-05,20:1.5432331565534696e-05,23:1.4172852388583124e-05,9:1.0329640645068139e-05,26:8.735177061680588e-07 22,29,24,13,5,15,17,14,18,12,19,10,0,2,3,4,6,11,1,16,8,27,20,23,9,26 |
ccb slot 12:0:0.9093628525733948,0:0.04226174205541611,17:0.018896808847784996,13:0.009150444529950619,14:0.005060152616351843,24:0.0038528849836438894,11:0.0037376414984464645,1:0.0027163256891071796,20:0.0019985607359558344,5:0.0015763206174597144,6:0.0005092258215881884,18:0.0003184932575095445,2:0.0002330887655261904,8:0.00017497778753750026,23:4.659605838241987e-05,10:4.272087971912697e-05,29:2.479964132362511e-05,3:8.60487580212066e-06,27:6.880749879201176e-06,16:5.5458899623772595e-06,15:4.874308160651708e-06,9:3.708174290295574e-06,26:3.1738302368466975e-06,19:2.801355094561586e-06,4:8.652203291603655e-07 12,0,17,13,14,24,11,1,20,5,6,18,2,8,23,10,29,3,27,16,15,9,26,19,4 |
ccb slot 5:0:0.28719252347946167,17:0.23356057703495026,29:0.17160779237747192,20:0.1328369677066803,0:0.07422535866498947,23:0.050119683146476746,1:0.021847186610102654,13:0.012630262412130833,2:0.004507853649556637,8:0.0024876149836927652,3:0.0022544104140251875,9:0.0015914351679384708,18:0.0013845351058989763,10:0.001123852445743978,4:0.0008636291604489088,15:0.0004619551182258874,16:0.0004587841685861349,6:0.0004078721103724092,11:0.00021510760416276753,14:0.00014530900807585567,24:3.345161894685589e-05,26:2.9229657229734585e-05,27:1.3438097084872425e-05,19:1.2410271210683277e-06 5,17,29,20,0,23,1,13,2,8,3,9,18,10,4,15,16,6,11,14,24,26,27,19 |
ccb slot 20:0:0.028376348316669464,0:0.1662101000547409,1:0.046988535672426224,17:0.6560971140861511,3:0.02463809959590435,2:0.022943779826164246,8:0.02021339163184166,4:0.011480750516057014,6:0.006486969999969006,27:0.005383896175771952,18:0.005046996288001537,10:0.0017316940939053893,16:0.0012900123838335276,9:0.0011327711399644613,13:0.000544899667147547,23:0.000498446635901928,11:0.00048043631250038743,14:0.00018104366608895361,19:0.00012088919174857438,24:6.899452273501083e-05,29:5.0261642172699794e-05,15:3.0958537536207587e-05,26:3.547019559846376e-06 20,0,1,17,3,2,8,4,6,27,18,10,16,9,13,23,11,14,19,24,29,15,26 |
ccb slot 29:0:0.14386186003684998,4:0.18966703116893768,11:0.2729467749595642,1:0.10815022885799408,17:0.10176316648721695,24:0.048249997198581696,3:0.034515734761953354,2:0.0317024290561676,6:0.029643042013049126,14:0.01419538538902998,10:0.008138692937791348,0:0.00682934420183301,13:0.003933712374418974,9:0.0023981353733688593,8:0.0013491454301401973,23:0.000978886615484953,15:0.0006223535747267306,27:0.00042564209434203804,18:0.0003683240502141416,19:0.00018579690367914736,26:5.759065970778465e-05,16:1.6690515622030944e-05 29,4,11,1,17,24,3,2,6,14,10,0,13,9,8,23,15,27,18,19,26,16 |
ccb slot 16:0:0.8358462452888489,18:0.14180654287338257,8:0.006622648332268,0:0.0048446557484567165,13:0.003651235019788146,17:0.002547427313402295,2:0.0023207622580230236,14:0.0007652127533219755,9:0.0003962431219406426,3:0.00039094872772693634,6:0.0003010313375853002,1:0.00015582605556119233,4:0.0001078778732335195,27:8.33657686598599e-05,11:6.325534195639193e-05,26:5.2438019338296726e-05,24:2.5939621991710737e-05,10:1.2438776138878893e-05,15:5.886784038011683e-06,23:1.0229091351732222e-08,19:7.580823080388654e-09 16,18,8,0,13,17,2,14,9,3,6,1,4,27,11,26,24,10,15,23,19 |
ccb slot 17:0:0.5127939581871033,2:0.4746686518192291,19:0.006616346072405577,1:0.001669980469159782,3:0.0010488936677575111,24:0.0009213163866661489,6:0.0007942019728943706,14:0.0006952053518034518,23:0.0005310842534527183,27:0.00010622834088280797,0:5.494915967574343e-05,8:2.4259865313069895e-05,26:2.4085793484118767e-05,10:1.763248656061478e-05,13:1.2499597687565256e-05,4:9.418990885023959e-06,11:6.62406728224596e-06,15:4.250239726388827e-06,9:3.168663909036695e-07 17,2,19,1,3,24,6,14,23,27,0,8,26,10,13,4,11,15,9 |
ccb slot 2:0:0.3009277284145355,11:0.2405196875333786,0:0.12718695402145386,1:0.10248230397701263,4:0.10110407322645187,27:0.0488734170794487,14:0.031138606369495392,23:0.027005093172192574,15:0.01463699247688055,13:0.0021626290399581194,9:0.001511908951215446,24:0.0014617646811529994,26:0.000723238626960665,8:0.00015963710029609501,10:6.141114135971293e-05,3:4.065587563673034e-05,6:2.3371310362563236e-06,19:1.6080829254860873e-06 2,11,0,1,4,27,14,23,15,13,9,24,26,8,10,3,6,19 |
ccb slot 3:0:0.057185981422662735,27:0.14134737849235535,24:0.11761204898357391,11:0.09371144324541092,0:0.5287960171699524,6:0.03242357447743416,8:0.011251688934862614,14:0.007142344955354929,1:0.0070684002712368965,23:0.0012641034554690123,9:0.0005852219182997942,13:0.0005638026632368565,19:0.0004846873343922198,15:0.0002985078317578882,26:0.00022339983843266964,10:3.1262432457879186e-05,4:1.0203940291830804e-05 3,27,24,11,0,6,8,14,1,23,9,13,19,15,26,10,4 |
ccb slot 1:0:0.1249222531914711,24:0.25583717226982117,14:0.12867441773414612,23:0.26537543535232544,13:0.08874479681253433,15:0.04395920783281326,11:0.04107809066772461,26:0.026856984943151474,0:0.01694386824965477,6:0.005332316737622023,9:0.0009168571559712291,8:0.0005701580666936934,10:0.00035485764965415,4:0.00030593250994570553,27:9.87778403214179e-05,19:2.8945323720108718e-05 1,24,14,23,13,15,11,26,0,6,9,8,10,4,27,19 |
ccb slot 0:0:0.7005100846290588,15:0.15935854613780975,26:0.10210220515727997,6:0.01650484837591648,27:0.012556466273963451,14:0.003727053524926305,10:0.0025744284503161907,23:0.0013873651623725891,11:0.0004973539034835994,13:0.00025413508410565555,24:0.0002187014470109716,8:0.00016339073772542179,19:8.715951116755605e-05,4:4.481669020606205e-05,9:1.3443200259644073e-05 0,15,26,6,27,14,10,23,11,13,24,8,19,4,9 |
ccb slot 8:0:0.9874762892723083,6:0.00831417366862297,24:0.0015088269719853997,19:0.0014199139550328255,13:0.0005207555368542671,4:0.0003495477430988103,23:0.00022233030176721513,11:0.0001492148294346407,10:1.3149796359357424e-05,27:9.886987754725851e-06,15:9.333793059340678e-06,9:2.8232302611286286e-06,14:2.0402019345056033e-06,26:1.7364958466714597e-06 8,6,24,19,13,4,23,11,10,27,15,9,14,26 |
ccb slot 14:0:0.12711836397647858,9:0.23751074075698853,10:0.3793737292289734,27:0.08924281597137451,24:0.07040458917617798,15:0.06249556690454483,11:0.02001812309026718,4:0.009080302901566029,26:0.0017807148396968842,23:0.0015691084554418921,19:0.0009121194598264992,13:0.0004805738863069564,6:1.3344042599783279e-05 14,9,10,27,24,15,11,4,26,23,19,13,6 |
ccb slot 24:0:0.9453869462013245,19:0.029324114322662354,23:0.017052331939339638,13:0.004684425424784422,11:0.0012589030666276813,10:0.0009999927133321762,26:0.0009100232855416834,15:0.00019236477965023369,6:0.00014357283362187445,27:4.12082408729475e-05,9:3.6369422105053673e-06,4:2.426173068670323e-06 24,19,23,13,11,10,26,15,6,27,9,4 |
ccb slot 19:0:0.07647673040628433,13:0.26458504796028137,27:0.08122498542070389,26:0.548874020576477,11:0.025309467688202858,15:0.0020130074117332697,6:0.00121505802962929,23:0.00012354919454082847,9:9.067041537491605e-05,4:4.7242716391338035e-05,10:4.006700328318402e-05 19,13,27,26,11,15,6,23,9,4,10 |

./vw --ccb_explore_adf -q UA --all_slots_loss --cb_type dr -f trained.model -d ${PROVIDED_EXAMPLE_FILE} && ./vw --ccb_explore_adf -q UA --all_slots_loss --cb_type dr -i trained.model -t -d  ${PROVIDED_EXAMPLE_FILE}

Version

9.6.0, 9.9.0, source

OS

Ubuntu 22.04 + MacOs

Language

Python, CLI

Additional context

Thanks for your time, and just ask if there's more information that you would need to solve this.

[ataymano]

Hi @NegatioN,
thank you for reporting this.
Let me share simplified repro for further debug:

data.txt:

{"c":{"_multi":[{"f":"1"},{"f":"2"}],"_slots":[{"_inc":[0,1]},{"_inc":[1]}]},"_outcomes":[{"_label_cost":1.0,"_a":[0,1],"_p":[0.5,0.5]},{"_label_cost":0.0,"_a":[1],"_p":[1]}]}

train the model:

vw --ccb_explore_adf --dsjson -d data.txt -f model.bin

crash:

vw --ccb_explore_adf --dsjson -d data.txt -i model.bin --epsilon 0 -t

[NegatioN]

That's great @ataymano, thanks for the prompt response 🙂
If you have some time though, can you explain quickly how the example I provided ends up with empty decision elements? Maybe there's something I could learn here. To my eyes it seems like all the slots have plenty of actions to choose from. (I'm not very experienced with Vowpal though.)

And, when you guys are happy with the PR, how long do you usually wait before releasing new a new version?

[ataymano]

Yeah but decisions are still made sequentially. So in this example we can be in trouble if we choose action 1 for the first slot. And that is enforced (in repro) during training process by positive cost for chosen 0 action (=> we learn that action 1 is better than 0 for the first slot) and turning off exploration in test command line (--epsilon 0) to deterministically choose what we think is good.

[NegatioN]

Hi @ataymano , I was wondering if there's any progress on this? It seemed to be going so smoothly with the PR. Just pinging in, in case it fell by the wayside over the holidays. 🙂

[NegatioN]

Could I trouble you guys to do a release of the library as well? We prefer not to build from source unless absolutely necessary.

[lalo]

@NegatioN how are you consuming VW? python package? or something else

[NegatioN]

@lalo , Python and Java bindings mainly, why?