第一次运行以下命令时出现问题：
make runtest -j8
输出如下：
.build_release/tools/caffe
.build_release/tools/caffe: symbol lookup error:
.build_release/tools/caffe: undefined symbol: _ZN6google16SetVersionStringERKSs Makefile:514: recipe for target 'runtest' failed
make: *** [runtest] Error 127
但是，当我再次运行make runtest -j8时：
错误信息不同：
*** Aborted at 1454750177 (unix time) try "date -d @1454750177" if you are using GNU date ***
PC: @ 0x7f144921d263 (unknown)
*** SIGSEGV (@0x706d742f) received by PID 15020 (TID 0x7f144d923780) from PID 1886221359; stack trace: ***
@ 0x7f14444992f0 (unknown)
@ 0x7f144921d263 (unknown)
@ 0x47fb22 caffe::MakeTempDir()
@ 0x47fd73 caffe::MakeTempFilename()
@ 0x480419 testing::internal::TestFactoryImpl<>::CreateTest()
@ 0x89a0c3 testing::internal::HandleExceptionsInMethodIfSupported<>()
@ 0x890cc5 testing::TestInfo::Run()
@ 0x890de5 testing::TestCase::Run()
@ 0x894128 testing::internal::UnitTestImpl::RunAllTests()
@ 0x8943b7 testing::UnitTest::Run()
@ 0x4667ff main
@ 0x7f1444484a40 (unknown)
@ 0x46de69 _start
Makefile:514: recipe for target 'runtest' failed
make: *** [runtest] Segmentation fault (core dumped)
没有问题时：
make all -j8
make test -j8
make pycaffe -j8
make matcaffe -j8
另外，当我跑：
sh examples/mnist/create_mnist.sh
有另一条错误消息：
Creating lmdb...
build/examples/mnist/convert_mnist_data.bin: symbol lookup error: build/examples/mnist/convert_mnist_data.bin: undefined symbol: _ZN6google15SetUsageMessageERKSs
build/examples/mnist/convert_mnist_data.bin: symbol lookup error: build/examples/mnist/convert_mnist_data.bin: undefined symbol: _ZN6google15SetUsageMessageERKSs
Done.
我不确定出了什么问题。上次安装cafffe，我在Ubuntu 14上运行顺畅。现在，我正在使用Ubuntu 15（我必须使用ubuntu 15，因为我遇到了ubuntu 14的另一个问题）。
有没有人遇到过这个问题？ 请帮我解决这个问题。任何想法都将不胜感激。