리눅스 환경에서 C/C++ 프로그램이 Segmentation fault 에러가 발생한 경우 (2)
오랜만에 먼지 낀 라즈베리 파이를 꺼내 지난번에 만들어 둔,
Raspberry Pi Zero(OTG)를 다른 컴퓨터에 연결해 가상 키보드 및 마우스로 쓰는 방법 (절대 좌표, 상대 좌표, 휠)
; https://www.sysnet.pe.kr/2/0/11369
모듈을 테스트하는데 "shutdown" 명령이 동작하질 않습니다. 때마침 배운 것도 있으니, ^^
리눅스 환경에서 C/C++ 프로그램이 Segmentation fault 에러가 발생한 경우
; https://www.sysnet.pe.kr/2/0/12208
실습으로 호출 스택을 떴는데,
root@raspberrypi:/home/pi# gdb /share/rasp_vusb_server.out
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Reading symbols from /share/rasp_vusb_server.out...done.
(gdb) r test
Starting program: /share/rasp_vusb_server.out test
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
init_openssl
completed: init_openssl
[New Thread 0xb6989450 (LWP 600)]
[New Thread 0xb6188450 (LWP 601)]
ipResolver prepared
keyboard/mouse opened
[New Thread 0xb5987450 (LWP 602)]
usbServer prepared
Press any key to exit...
Client connection information:
IP: 172.30.1.37, Port: 54863
[New Thread 0xb4fff450 (LWP 603)]
Client connection information:
IP: 172.30.1.37, Port: 51683
[New Thread 0xb47fe450 (LWP 604)]
recvBytes == 1
Thread 2 "rasp_vusb_serve" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb6989450 (LWP 600)]
std::basic_ios<char, std::char_traits<char> >::widen () at /usr/include/c++/6/bits/basic_ios.h:450
450 { return __check_facet(_M_ctype).widen(__c); }
(gdb) bt
#0 std::basic_ios<char, std::char_traits<char> >::widen () at /usr/include/c++/6/bits/basic_ios.h:450
#1 std::endl<char, std::char_traits<char> > () at /usr/include/c++/6/ostream:591
#2 std::ostream::operator<< () at /usr/include/c++/6/ostream:113
#3 UsbEmulator::ProcessUsbInput () at /home/pi/projects/rasp_vusb_server/UsbEmulator.cpp:105
#4 operator() () at /home/pi/projects/rasp_vusb_server/UsbEmulator.cpp:72
#5 _M_invoke<> () at /usr/include/c++/6/functional:1391
#6 operator() () at /usr/include/c++/6/functional:1380
#7 _M_run () at /usr/include/c++/6/thread:197
#8 0xb6ca39dc in ?? () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#9 0xb6b37fc4 in start_thread (arg=0xb6989450) at pthread_create.c:458
#10 0xb6ac4038 in ?? () at ../sysdeps/unix/sysv/linux/arm/clone.S:76 from /lib/arm-linux-gnueabihf/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb)
분명히 "cout" 라인에서 Segmentation fault 오류가 발생합니다. 혹시나 싶어 그 라인을 printf로 바꿨더니,
printf("shutting down...\n");
// cout << "shutting down..." << endl;
오호~~~ 잘 동작합니다. 그런데, 이유를 모르겠군요. 혹시나 소스코드(
https://github.com/stjeong/rasp_vusb/blob/master/rasp_vusb_server/UsbEmulator.cpp#L51)를 보시고 원인이 짐작되시는 분이 있다면 덧글 부탁드립니다. ^^
[이 글에 대해서 여러분들과 의견을 공유하고 싶습니다. 틀리거나 미흡한 부분 또는 의문 사항이 있으시면 언제든 댓글 남겨주십시오.]