리눅스 환경에서 C/C++ 프로그램이 Segmentation fault 에러가 발생한 경우
리눅스 환경에 낯설다 보니 ^^ 회사 동료가 빠르게 오류 원인을 파악하는 방법을 알려줬습니다. 우선, (아마도 container 환경이라면 거의 없을 텐데) gdb를 설치하고,
apt-get update && apt-get install -y --no-install-recommends gdb
gdb를 대상 실행 모듈을 로드하도록 실행한 후, (이 글에서는 dotnet 프로그램으로 가정)
$ gdb dotnet
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Reading symbols from dotnet...(no debugging symbols found)...done.
명령행 인자가 있다면 함께 명시하면서 "r"로 실행을 시키면,
(gdb) r "razor21_sample.dll"
Starting program: /usr/bin/dotnet "razor21_sample.dll"
warning: Error disabling address space randomization: Operation not permitted
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fe676029700 (LWP 745)]
...[생략]...
[New Thread 0x7fe667fff700 (LWP 790)]
Thread 1 "dotnet" received signal SIGSEGV, Segmentation fault.
0x00007f0a363b5c0c in construct<unsigned char, unsigned char const&> ()
at /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/ext/new_allocator.h:136
136 /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/ext/new_allocator.h: No such file or directory.
Segmentation fault 오류가 발생한 시점에 서게 되고, 이때 bt 명령을 통해 호출 스택을 살필 수 있습니다.
(gdb) bt
#0 0x00007fe6740bfc0c in construct<unsigned char, unsigned char const&> ()
at /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/ext/new_allocator.h:136
#1 construct<unsigned char, unsigned char const&> ()
at /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/alloc_traits.h:475
#2 push_back ()
at /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_vector.h:1079
#3 TestSegFaultMethod ()
at /home/testusr/projects/libTest/shared/TestInfo.cpp:2315
#4 0x00007fe6740bf6d8 in TestResolve ()
at /home/testusr/projects/libTest/shared/TestInfo.cpp:2155
#5 0x00007fe6740e3d4d in TestCall ()
at /home/testusr/projects/libTest/shared/TestApp.cpp:1391
#6 0x00007fe6740e3439 in TestMethod ()
at /home/testusr/projects/libTest/shared/TestApp.cpp:1273
#7 0x00007fe6740e2e49 in TestJIT ()
at /home/testusr/projects/libTest/shared/TestApp.cpp:1178
#8 0x00007fe677132f3c in EEToProfInterfaceImpl::TestJIT(unsigned long, int) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#9 0x00007fe67726d222 in MethodDesc::JitCompileCodeLockedEventWrapper(PrepareCodeConfig*, ListLockEntryBase<NativeCodeVersion>*) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#10 0x00007fe67726cbb0 in MethodDesc::JitCompileCode(PrepareCodeConfig*) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#11 0x00007fe67726c937 in MethodDesc::PrepareILBasedCode(PrepareCodeConfig*) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#12 0x00007fe67726ef15 in MethodDesc::DoPrestub(MethodTable*) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#13 0x00007fe67726e844 in PreStubWorker ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#14 0x00007fe6771f0bc4 in ThePreStub ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#15 0x00007fe6771efedf in CallDescrWorkerInternal ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#16 0x00007fe67711060c in MethodDescCallSite::CallTargetWorker(unsigned long const*, unsigned long*, int) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#17 0x00007fe677211076 in RunMain(MethodDesc*, short, int*, PtrArray**) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#18 0x00007fe677211315 in Assembly::ExecuteMainMethod(PtrArray**, int) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#19 0x00007fe677059ec2 in CorHost2::ExecuteAssembly(unsigned int, char16_t const*, int, char16_t const**, unsigned int*) ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
#20 0x00007fe677034fe4 in coreclr_execute_assembly ()
from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libcoreclr.so
---Type <return> to continue, or q <return> to quit---
#21 0x00007fe67780c84d in ?? () from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libhostpolicy.so
#22 0x00007fe6777ff2cd in ?? () from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libhostpolicy.so
#23 0x00007fe6777ffb1c in corehost_main () from /usr/share/dotnet/shared/Microsoft.NETCore.App/2.1.17/libhostpolicy.so
#24 0x00007fe677ab29cf in ?? () from /usr/share/dotnet/host/fxr/2.1.17/libhostfxr.so
#25 0x00007fe677abdf8c in ?? () from /usr/share/dotnet/host/fxr/2.1.17/libhostfxr.so
#26 0x00007fe677abf0e5 in ?? () from /usr/share/dotnet/host/fxr/2.1.17/libhostfxr.so
#27 0x00007fe677abe659 in ?? () from /usr/share/dotnet/host/fxr/2.1.17/libhostfxr.so
#28 0x00007fe677ab2c1c in hostfxr_main_startupinfo () from /usr/share/dotnet/host/fxr/2.1.17/libhostfxr.so
#29 0x000000000040ac74 in ?? ()
#30 0x000000000040af05 in ?? ()
#31 0x00007fe677d232e1 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#32 0x0000000000408a54 in _start ()
(gdb)
이 정도만 확인할 수 있어도, 어떻게 원인을 탐색 및 해결해야 할지 큰 도움이 됩니다. ^^
[이 글에 대해서 여러분들과 의견을 공유하고 싶습니다. 틀리거나 미흡한 부분 또는 의문 사항이 있으시면 언제든 댓글 남겨주십시오.]