One example

Thu Apr 14 20:10:49 [conn70] building new index on

for test.jstests_or2
Thu Apr 14 20:10:49 [conn70] done for 0 records 0 secs
Thu Apr 14 20:10:49 [conn70] Assertion: 13262:$or requires nonempty array
0x561ce9 0x52e3e6 0x7deb23 0x66ad31 0x78ba05 0x792b75 0x92f76f 0x5d40e5 0x9370c0 0x34dee06407 0x34de2d4b0d
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(_ZN5mongo11msgassertedEiPKc+0x129) [0x561ce9]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(_ZN5mongo15FieldRangeOrSetC1EPKcRKNS_7BSONObjEb+0x866) [0x52e3e6]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(_ZN5mongo16MultiPlanScannerC1EPKcRKNS_7BSONObjES5_PKNS_11BSONElementEbS5_S5_bb+0x153) [0x7deb23]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(ZN5mongo8runQueryERNS_7MessageERNS_12QueryMessageERNS_5CurOpES1+0xc11) [0x66ad31]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod [0x78ba05]
/home/yellow/buildbot/Linux_64bit_v8//mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_11HostAndPortE+0xdc5) [0x792b75]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(_ZN5mongo16MyMessageHandler7processERNS_7MessageEPNS_21AbstractMessagingPortEPNS_9LastErrorE+0x7f) [0x92f76f]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(_ZN5mongo3pms9threadRunEPNS_13MessagingPortE+0x3e5) [0x5d40e5]
/home/yellow/buildbot/Linux_64bit_v8/mongo/mongod(thread_proxy+0x80) [0x9370c0]
/lib64/libpthread.so.0 [0x34dee06407]
/lib64/libc.so.6(clone+0x6d) [0x34de2d4b0d]