Seen while running sharding_passthrough.js

*******************************************
Test : jstests/where3.js ...
m31000| Tue Apr 26 11:08:29 [conn1] DROP: test.where3
m30001| Tue Apr 26 11:08:29 [conn4] CMD: drop test.where3
m30001| Tue Apr 26 11:08:29 [conn4] building new index on

for test.where3
m30001| Tue Apr 26 11:08:29 [conn4] done for 0 records 0 secs
19ms
m31000| Tue Apr 26 11:08:29 [mongosMain] dbexit: received signal 15 rc:0 received si\
gnal 15
m31000| Tue Apr 26 11:08:29 [mongosMain] CursorCache at shutdown - sharded: 0 pass\
through: 56
m31000| mongos(41256,0x100f87000) malloc: *** error for object 0x100333ea0: pointer \
being freed was not allocated
m31000| *** set a breakpoint in malloc_error_break to debug
m30000| Tue Apr 26 11:08:29 [conn8] end connection 127.0.0.1:59240
m30000| Tue Apr 26 11:08:29 [conn12] end connection 127.0.0.1:59247
m30000| Tue Apr 26 11:08:29 [conn14] end connection 127.0.0.1:59257
m30001| Tue Apr 26 11:08:29 [conn8] end connection 127.0.0.1:59246
m30001| Tue Apr 26 11:08:29 [conn10] end connection 127.0.0.1:59253
m30001| Tue Apr 26 11:08:29 [conn12] end connection 127.0.0.1:59255
m30000| Tue Apr 26 11:08:40 [conn10] end connection 127.0.0.1:59241
m30000| Tue Apr 26 11:08:40 [conn4] end connection 127.0.0.1:59236
m30001| Tue Apr 26 11:08:40 [conn4] end connection 127.0.0.1:59243