This just happened on one of the masters on one of my replica sets while I was creating an index:

Thu Apr 7 17:26:34 Invalid access at address: 0x3255000

Thu Apr 7 17:26:34 Got signal: 11 (Segmentation fault).

Thu Apr 7 17:26:34 Backtrace:
0x8a2e59 0x8a3430 0x7f220ddeb8f0 0x7f220d33208b 0x7f220db707be
0x7f220db7104c 0x6d6a74 0x6d0694 0x7dae1e 0x7dc741 0x642c25 0x6477c6
0x752225 0x757938 0x8a3b3e 0x8b6a40 0x7f220dde29ca 0x7f220d39170d
/usr/bin/mongod(_ZN5mongo10abruptQuitEi+0x399) [0x8a2e59]
/usr/bin/mongod(_ZN5mongo24abruptQuitWithAddrSignalEiP7siginfoPv
+0x220) [0x8a3430]
/lib/libpthread.so.0(+0xf8f0) [0x7f220ddeb8f0]
/lib/libc.so.6(memcpy+0x3fb) [0x7f220d33208b]
/usr/lib/libstdc++.so.6(_ZNSs4_Rep8_M_cloneERKSaIcEm+0x7e)
[0x7f220db707be]
/usr/lib/libstdc++.so.6(_ZNSsC1ERKSs+0x3c) [0x7f220db7104c]
/usr/bin/
mongod(_ZNK5mongo11ReplSetImpl16_summarizeStatusERNS_14BSONObjBuilderE
+0xa94) [0x6d6a74]
/usr/bin/
mongod(_ZN5mongo19CmdReplSetGetStatus3runERKSsRNS_7BSONObjERSsRNS_14BSONObjBuilderEb
+0x114) [0x6d0694]
/usr/bin/
mongod(_ZN5mongo11execCommandEPNS_7CommandERNS_6ClientEiPKcRNS_7BSONObjERNS_14BSONObjBuilderEb
+0x5ae) [0x7dae1e]
/usr/bin/
mongod(_ZN5mongo12_runCommandsEPKcRNS_7BSONObjERNS_10BufBuilderERNS_14BSONObjBuilderEbi
+0x831) [0x7dc741]
/usr/bin/
mongod(_ZN5mongo11runCommandsEPKcRNS_7BSONObjERNS_5CurOpERNS_10BufBuilderERNS_14BSONObjBuilderEbi
+0x35) [0x642c25]
/usr/bin/
mongod(ZN5mongo8runQueryERNS_7MessageERNS_12QueryMessageERNS_5CurOpES1
+0x2e86) [0x6477c6]
/usr/bin/mongod() [0x752225]
/usr/bin/
mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_8SockAddrE
+0x5b8) [0x757938]
/usr/bin/mongod(_ZN5mongo10connThreadEPNS_13MessagingPortE+0x21e)
[0x8a3b3e]
/usr/bin/mongod(thread_proxy+0x80) [0x8b6a40]
/lib/libpthread.so.0(+0x69ca) [0x7f220dde29ca]
/lib/libc.so.6(clone+0x6d) [0x7f220d39170d]

Thu Apr 7 17:26:34 dbexit:
Thu Apr 7 17:26:34 [conn30] shutdown: going to close listening
sockets...
Thu Apr 7 17:26:34 [conn30] closing listening socket: 5
Thu Apr 7 17:26:34 [conn30] closing listening socket: 6
Thu Apr 7 17:26:34 [conn30] closing listening socket: 7
Thu Apr 7 17:26:34 [conn30] closing listening socket: 8
Thu Apr 7 17:26:34 [conn30] removing socket file: /tmp/
mongodb-27018.sock
Thu Apr 7 17:26:34 [conn30] removing socket file: /tmp/
mongodb-28018.sock
Thu Apr 7 17:26:34 [conn30] shutdown: going to flush diaglog...
Thu Apr 7 17:26:34 [conn30] shutdown: going to close sockets...
Thu Apr 7 17:26:34 [conn30] shutdown: waiting for fs preallocator...
Thu Apr 7 17:26:34 [conn30] shutdown: closing all files...
1/55 1%
Thu Apr 7 17:26:37 Invalid access at address: 0x7f220273e8c0

Thu Apr 7 17:26:37 Got signal: 11 (Segmentation fault).

Thu Apr 7 17:26:37 Backtrace:
0x8a2e59 0x8a3430 0x7f220ddeb8f0 0x730420 0x73048a 0x77447d 0x710acc
0x70ee12 0x757044 0x758caf 0x8a3b3e 0x8b6a40 0x7f220dde29ca
0x7f220d39170d
/usr/bin/mongod(_ZN5mongo10abruptQuitEi+0x399) [0x8a2e59]
/usr/bin/mongod(_ZN5mongo24abruptQuitWithAddrSignalEiP7siginfoPv
+0x220) [0x8a3430]
/lib/libpthread.so.0(+0xf8f0) [0x7f220ddeb8f0]
/usr/bin/mongod(_ZN5mongo16NamespaceDetails6_allocEPKci+0) [0x730420]
/usr/bin/mongod(_ZN5mongo16NamespaceDetails5allocEPKciRNS_7DiskLocE
+0x3a) [0x73048a]
/usr/bin/
mongod(_ZN5mongo11DataFileMgr17fast_oplog_insertEPNS_16NamespaceDetailsEPKci
+0x19d) [0x77447d]
/usr/bin/mongod() [0x710acc]
/usr/bin/mongod(_ZN5mongo5logOpEPKcS1_RKNS_7BSONObjEPS2_Pb+0x42)
[0x70ee12]
/usr/bin/mongod(_ZN5mongo14receivedInsertERNS_7MessageERNS_5CurOpE
+0x394) [0x757044]
/usr/bin/
mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_8SockAddrE
+0x192f) [0x758caf]
/usr/bin/mongod(_ZN5mongo10connThreadEPNS_13MessagingPortE+0x21e)
[0x8a3b3e]
/usr/bin/mongod(thread_proxy+0x80) [0x8b6a40]
/lib/libpthread.so.0(+0x69ca) [0x7f220dde29ca]
/lib/libc.so.6(clone+0x6d) [0x7f220d39170d]

Thu Apr 7 17:26:37 dbexit: ; exiting immediately
Thu Apr 7 17:26:38 ERROR: Client::~Client _context should be null but
is not; client:conn