underlying gdb process has been killed after running to first breakpoint

[chisaipete]

Describe the bug
I load my binary, manually set a break-point several statements into my main function, then click run. The program spawns multiple threads as expected (it's using SDL2) but once it reaches the first break-point, execution stops, the gui is updated, and I see the following in red text in the gdbgui console:

The underlying gdb process has been killed. This tab will no longer function as expected.
Error occurred on server when running gdb command: gdb is not running
Error occurred on server when running gdb command: gdb is not running
Error occurred on server when running gdb command: gdb is not running
Error occurred on server when running gdb command: gdb is not running
...

Screenshots

Please complete the following information:

• OS: Windows 10
• gdbgui version (gdbgui -v): 0.12.0.0
• gdb version (gdb -v): 8.1
• browser [e.g. chrome, safari]: chrome
• python packages (pip freeze):
  cffi==1.11.5
  click==6.7
  Flask==0.12.4
  Flask-Compress==1.4.0
  Flask-SocketIO==2.9.6
  gdbgui==0.12.0.0
  gevent==1.3.4
  greenlet==0.4.13
  itsdangerous==0.24
  Jinja2==2.10
  MarkupSafe==1.0
  pycparser==2.18
  pygdbmi==0.8.3.0
  Pygments==2.2.0
  python-engineio==2.2.0
  python-socketio==2.0.0
  six==1.11.0
  Werkzeug==0.14.1

Additional context
If it helps, I'm using the neuwin.net Mingw distro. Pretty light as far as mingw on windows gets.

[chisaipete]

I should also mention that I can debug this and other programs just fine using gdb on the command line.

[cs01]

Thanks for filing. It might be a gdb bug in its machine interface implementation. Unfortunately with the info you provided I don't know what the cause is. Maybe if you re-run with strace and post results here it will help.

[chisaipete]

I'm not sure what you mean. Is "strace" a specific gdb or gdbgui command? I'm running on Windows 10, isn't strace a linux utility?

[cs01]

Yes strace intercepts and prints all system calls. You're right that it might not be available on windows (I am pretty Linux centric). It might be available as a package in mingw. Or there might be another utility available to debug the issue.

What I'm really looking for is a way to see what is causing the abrupt exit, which is likely due to a segfault. The info you provided is not quite specific enough to be actionable since I can't tell what the root cause is (lots of things can cause a segfault).

[msik314]

I am running into this issue, too.

The differenences in my information are this:
gdbgui version: 0.13.1.2
browser: Firefox
python packages:
Click==7.0
pipx==0.13.1.1
userpath==1.1.0

I do have strace on Windows, and this is the relevant part of my strace log:
--- Process 3928 thread 9116 exited with status 0x0
--- Process 3928 thread 10232 exited with status 0x0
--- Process 3928 thread 6772 created
--- Process 948 thread 8276 created
--- Process 1532 thread 6536 created
--- Process 8376 thread 8552 created
--- Process 3928 thread 10040 exited with status 0x0
--- Process 3928 thread 420 created
--- Process 3928 thread 6772 exited with status 0x0
--- Process 948 thread 3672 exited with status 0x0
--- Process 3928 thread 9884 created
--- Process 9492 loaded C:\Windows\System32\cryptbase.dll at 00007ff9a2350000
--- Process 9492, exception c0000005 at 00007ff9a3bb42e0
--- Process 8376 thread 4292 created
--- Process 9492 thread 9672 exited with status 0xc0000005
--- Process 9492 exited with status 0xc0000005
--- Process 9320 exited with status 0xc0000005
--- Process 5636 thread 9676 created
--- Process 5636 thread 6036 created
--- Process 5636 thread 9676 exited with status 0x0
--- Process 5636 thread 6036 exited with status 0x0

Exception 0xc0000005 is the exception code for a Memory Access Violation a.k.a Segfault. I can provide the full log if necessary.

Update:
I did some digging and I think that gdb is crashing when trying to read the registers. At least in my case, this is then an issue with gdb itself.

[dgtlrift]

Is there a diagnostic code that gdbgui can output when it catches a segv from GDB? I'm seeing the same error code when starting an app via GDB.

[w809291634]

gcc版本出现问题，找一个适合的mingw，下面是我用的版本，测试能够使用
winlibs-x86_64-posix-seh-gcc-7.5.0-mingw-w64-7.0.0-r1.7z