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Crash that occur only in debug mode with a simple project

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  • D deleted343

    @JoeCFD The crash occured before deleting the pointer. Otherwise, the program is correct.

    KroMignonK Offline
    KroMignonK Offline
    KroMignon
    wrote on last edited by
    #8

    @embeddedmz said in Crash that occur only in debug mode with a simple project:

    The crash occured before deleting the pointer. Otherwise, the program is correct.

    For me, it looks like a "double free" issue.
    Are you sure m_Internals is valid when FoobarManager destructor is called?

    It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

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    • KroMignonK KroMignon

      @embeddedmz said in Crash that occur only in debug mode with a simple project:

      The crash occured before deleting the pointer. Otherwise, the program is correct.

      For me, it looks like a "double free" issue.
      Are you sure m_Internals is valid when FoobarManager destructor is called?

      D Offline
      D Offline
      deleted343
      wrote on last edited by deleted343
      #9

      @KroMignon It's the PIMPL idiom and there's nothing wrong with the code, I used the same style many times on multiple platforms and the issue is not with the code but with the tool. I already put a breakpoint in the destructor and it's not called before the crash !

      Like I just said before, with Visual Studio 2019 and vcpkg there's no bugs ! Can you please clone the project and check that it's exiting properly ? Maybe my Qt Creator is mixing DLLs or something like that.

      jsulmJ KroMignonK 2 Replies Last reply
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      • D deleted343

        @KroMignon It's the PIMPL idiom and there's nothing wrong with the code, I used the same style many times on multiple platforms and the issue is not with the code but with the tool. I already put a breakpoint in the destructor and it's not called before the crash !

        Like I just said before, with Visual Studio 2019 and vcpkg there's no bugs ! Can you please clone the project and check that it's exiting properly ? Maybe my Qt Creator is mixing DLLs or something like that.

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #10

        @embeddedmz said in Crash that occur only in debug mode with a simple project:

        but with the tool

        How so? QtCreator is an IDE, nothing more. If there is an issue outside of your code then it is in Qt. But I doubt that. Different behaviour of release and debug builds is usually a sign for a bug in the code. And different compilers can behave differently in such situations.

        https://forum.qt.io/topic/113070/qt-code-of-conduct

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        • jsulmJ jsulm

          @embeddedmz Does FoobarManager have a parent? You could have a double delete.
          And this issue has absolutely nothing to do with QtCreator which is an IDE.

          D Offline
          D Offline
          deleted343
          wrote on last edited by
          #11

          @jsulm No it doesn't have a parent, and I'm competent enough to know these issues. It's an "empty" project, please take a look at it !

          Even if I do nothing in the destructor or I remove all delete statements everywhere it still crashes only with Qt Creator in debug mode.

          I still believe it's the fault of Qt Creator maybe it's using different DLLs or something like that or a compiling issue.

          jsulmJ J.HilkJ 2 Replies Last reply
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          • Christian EhrlicherC Offline
            Christian EhrlicherC Offline
            Christian Ehrlicher
            Lifetime Qt Champion
            wrote on last edited by
            #12

            @embeddedmz said in Crash that occur only in debug mode with a simple project:

            It's an "empty" project, please take a look at it !

            Where? There is no minimal, compilable example somewhere...

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

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            • D deleted343

              @jsulm No it doesn't have a parent, and I'm competent enough to know these issues. It's an "empty" project, please take a look at it !

              Even if I do nothing in the destructor or I remove all delete statements everywhere it still crashes only with Qt Creator in debug mode.

              I still believe it's the fault of Qt Creator maybe it's using different DLLs or something like that or a compiling issue.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by jsulm
              #13

              @embeddedmz What Qt version and compiler do you use?
              I just tested on Linux with Qt 5.12.8 and QtCreator 4.11.0 in debug mode and have no crashes.

              https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • D deleted343

                @KroMignon It's the PIMPL idiom and there's nothing wrong with the code, I used the same style many times on multiple platforms and the issue is not with the code but with the tool. I already put a breakpoint in the destructor and it's not called before the crash !

                Like I just said before, with Visual Studio 2019 and vcpkg there's no bugs ! Can you please clone the project and check that it's exiting properly ? Maybe my Qt Creator is mixing DLLs or something like that.

                KroMignonK Offline
                KroMignonK Offline
                KroMignon
                wrote on last edited by
                #14

                @embeddedmz said in Crash that occur only in debug mode with a simple project:

                Like I just said before, with Visual Studio 2019 and vcpkg there's no bugs !

                Maybe, but are you sure m_Internals always have a valid value?
                Is it initialized to 0/nullptr when no used?
                Be aware with MSVC, MSVC is working differently between release/debug compilation. In debug, MSVC force uninitialized pointer to 0, this may mask some initialization issues!

                It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

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                • D deleted343

                  @jsulm No it doesn't have a parent, and I'm competent enough to know these issues. It's an "empty" project, please take a look at it !

                  Even if I do nothing in the destructor or I remove all delete statements everywhere it still crashes only with Qt Creator in debug mode.

                  I still believe it's the fault of Qt Creator maybe it's using different DLLs or something like that or a compiling issue.

                  J.HilkJ Offline
                  J.HilkJ Offline
                  J.Hilk
                  Moderators
                  wrote on last edited by J.Hilk
                  #15

                  @embeddedmz said in Crash that occur only in debug mode with a simple project:

                  I still believe it's the fault of Qt Creator maybe it's using different DLLs or something like that or a compiling issue.

                  Nope, works perfectly fine on MacOS ( Qt 5.15.2 & QtC 4.15.0)


                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                  Q: What's that?
                  A: It's blue light.
                  Q: What does it do?
                  A: It turns blue.

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                  • jsulmJ jsulm

                    @embeddedmz said in Crash that occur only in debug mode with a simple project:

                    but with the tool

                    How so? QtCreator is an IDE, nothing more. If there is an issue outside of your code then it is in Qt. But I doubt that. Different behaviour of release and debug builds is usually a sign for a bug in the code. And different compilers can behave differently in such situations.

                    D Offline
                    D Offline
                    deleted343
                    wrote on last edited by
                    #16

                    @jsulm said in Crash that occur only in debug mode with a simple project:

                    How so? QtCreator is an IDE, nothing more. If there is an issue outside of your code then it is in Qt. But I doubt that. Different behaviour of release and debug builds is usually a sign for a bug in the code. And different compilers can behave differently in such situations.

                    If your execution environement points to bad shared objects (DLLs in that case) your application can start and crash randomly during run time.

                    I have to check the PATH folder or something like that but this stuff is usually handled automatically by Qt Creator when debugging. Using a dependency walker cannot help because in the output directory, Qt DLLs are not copied.

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                    • Christian EhrlicherC Christian Ehrlicher

                      @embeddedmz said in Crash that occur only in debug mode with a simple project:

                      It's an "empty" project, please take a look at it !

                      Where? There is no minimal, compilable example somewhere...

                      D Offline
                      D Offline
                      deleted343
                      wrote on last edited by
                      #17

                      @Christian-Ehrlicher I have already posted the link in the question : https://github.com/embeddedmz/QtCreatorDebugAppCrash

                      JonBJ 1 Reply Last reply
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                      • D deleted343

                        @Christian-Ehrlicher I have already posted the link in the question : https://github.com/embeddedmz/QtCreatorDebugAppCrash

                        JonBJ Online
                        JonBJ Online
                        JonB
                        wrote on last edited by JonB
                        #18

                        @embeddedmz
                        Does it not crash if you do put in Qt::QueuedConnection? You are connecting signal and slot while in one thread, so that will be direct connection, then moving one side into a thread. I do not know whether Qt adjusts the connection for you to become queued in this case, you need queued connections between different threads.

                        J.HilkJ D 2 Replies Last reply
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                        • JonBJ JonB

                          @embeddedmz
                          Does it not crash if you do put in Qt::QueuedConnection? You are connecting signal and slot while in one thread, so that will be direct connection, then moving one side into a thread. I do not know whether Qt adjusts the connection for you to become queued in this case, you need queued connections between different threads.

                          J.HilkJ Offline
                          J.HilkJ Offline
                          J.Hilk
                          Moderators
                          wrote on last edited by J.Hilk
                          #19

                          @JonB If its on Qt::AutoConnection (the default, when not specified) then it should "look that up during runtime", IIRC. And adjust accordingly

                          I would do without the raw delete and rather use deleteLater(), some Qt internals do not clean up properly/play nicely when you call the raw delete on QObjects


                          Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                          Q: What's that?
                          A: It's blue light.
                          Q: What does it do?
                          A: It turns blue.

                          1 Reply Last reply
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                          • JonBJ JonB

                            @embeddedmz
                            Does it not crash if you do put in Qt::QueuedConnection? You are connecting signal and slot while in one thread, so that will be direct connection, then moving one side into a thread. I do not know whether Qt adjusts the connection for you to become queued in this case, you need queued connections between different threads.

                            D Offline
                            D Offline
                            deleted343
                            wrote on last edited by deleted343
                            #20

                            @JonB I still have the same problem.

                            I'm sure it's Qt Creator using some bad DLLs in debug mode but I don't know how to check that and how to fix it.

                            JonBJ 1 Reply Last reply
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                            • D deleted343

                              @JonB I still have the same problem.

                              I'm sure it's Qt Creator using some bad DLLs in debug mode but I don't know how to check that and how to fix it.

                              JonBJ Online
                              JonBJ Online
                              JonB
                              wrote on last edited by
                              #21

                              @embeddedmz
                              Looking at your stack trace, what is the QtVisualStudioDebuggerBug file for which you do not have the source? That name looks a little bit worrying?

                              1 Reply Last reply
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                              • D Offline
                                D Offline
                                deleted343
                                wrote on last edited by
                                #22

                                Now, I can't even build after updating VS2019 :

                                D:\DevProjects\QtVisualStudioDebuggerBug\CMakeLists.txt:3: erreur : No CMAKE_CXX_COMPILER could be found. Tell CMake where to find the compiler by setting either the environment variable "CXX" or the CMake cache entry CMAKE_CXX_COMPILER to the full path to the compiler, or to the compiler name if it is in the PATH.

                                Any insights on how to fix this ?

                                Thanks.

                                1 Reply Last reply
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                                • D Offline
                                  D Offline
                                  deleted343
                                  wrote on last edited by deleted343
                                  #23

                                  I reinstalled Qt, the issue disappeared but now I'm having the commercial version of Qt ??!!?? Fixed this last issue by creating a new Qt account. Please Qt Company, fix your installer.

                                  1 Reply Last reply
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