segmentation fault
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@Milav Forget about
qDebug() << *mosq;it's only going to work if operator<< was overloaded for that class, apparently it isn't, but this is not an issue.
Can you try to run the app directly with gdb? -
@Milav Forget about
qDebug() << *mosq;it's only going to work if operator<< was overloaded for that class, apparently it isn't, but this is not an issue.
Can you try to run the app directly with gdb?Can you try to run the app directly with gdb?
I know this is not the place for a long explanation. But when OP says
I make a qt application for Embedded Custom Board
I thought (knowing nothing about this) it meant he is doing something like )cross-)compiling of whatever but the app runs "on the board", so he might not have/be able to use a debugger? Can you explain to me in one sentence what the OP's enthronement actually is, I'd like to have the vaguest understanding....
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@Milav Forget about
qDebug() << *mosq;it's only going to work if operator<< was overloaded for that class, apparently it isn't, but this is not an issue.
Can you try to run the app directly with gdb?@jsulm said in segmentation fault:
Forget about
qDebug() << *mosq;okay thank you.
@jsulm said in segmentation fault:
Can you try to run the app directly with gdb?
yes i tried but , debugger give me error,
the error is shown in below image.
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@jsulm said in segmentation fault:
Forget about
qDebug() << *mosq;okay thank you.
@jsulm said in segmentation fault:
Can you try to run the app directly with gdb?
yes i tried but , debugger give me error,
the error is shown in below image.
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@jsulm said in segmentation fault:
Forget about
qDebug() << *mosq;okay thank you.
@jsulm said in segmentation fault:
Can you try to run the app directly with gdb?
yes i tried but , debugger give me error,
the error is shown in below image.
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@JonB said in segmentation fault:
app directly in gdb (from the command-line)
actually, i am new in this.
give me some time i explore it and give you answer.
i don't know how i run app in gdb.
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- Open Command Prompt/terminal/shell.
cdto where your executable is.gdb <your-executable>
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but in gdb how i see "stack trace" ?
what classes i use from List of classes of commands?
please tell me
@Milav In gdb enter bt and press enter after your app crashed
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i enter the gdb command as following .
tdp0009@tdp0009-desktop:~/Teq_Projects/Aug_2019/HMI/Firmware/QT/Desktop_Application/11-oct/qt-mqtt-example/build-qt-mosquitto-Desktop-Release$ gdb qt-mosquitto GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) 7.11.1 Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from qt-mosquitto...(no debugging symbols found)...done. (gdb) bt No stack. (gdb) No stack. (gdb) -
i enter the gdb command as following .
tdp0009@tdp0009-desktop:~/Teq_Projects/Aug_2019/HMI/Firmware/QT/Desktop_Application/11-oct/qt-mqtt-example/build-qt-mosquitto-Desktop-Release$ gdb qt-mosquitto GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) 7.11.1 Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from qt-mosquitto...(no debugging symbols found)...done. (gdb) bt No stack. (gdb) No stack. (gdb) -
@Milav
Typerunfirst to run your program! Then if it crashes typebt. You could typeman gdbfrom the command-line, orhelpfrom withingdblike the message states. We had to learn to do that....thank you for your help.
i run gdb from development host machine.
here i send the output of that.
tdp0009@tdp0009-desktop:~/Teq_Projects/Aug_2019/HMI/Phytec_Toolchain/arm-cortexa8-linux-gnueabihf/bin$ ./arm-cortexa8-linux-gnueabihf-gdb GNU gdb (GDB) 7.5 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "--host=i686-host-linux-gnu --target=arm-cortexa8-linux-gnueabihf". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. (gdb) target extended 192.168.5.52:2345 Remote debugging using 192.168.5.52:2345 (gdb) set remote exec-file /opt/milav/qt-mosquitto (gdb) run Starting program: Program received signal SIGILL, Illegal instruction. 0x404df208 in ?? () (gdb) bt #0 0x404df208 in ?? () Cannot access memory at address 0x0 #1 0x404092c0 in ?? () Cannot access memory at address 0x0 #2 0x404092c0 in ?? () Cannot access memory at address 0x0 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb)i think you got what you want.
looking forward hearing from you.
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thank you for your help.
i run gdb from development host machine.
here i send the output of that.
tdp0009@tdp0009-desktop:~/Teq_Projects/Aug_2019/HMI/Phytec_Toolchain/arm-cortexa8-linux-gnueabihf/bin$ ./arm-cortexa8-linux-gnueabihf-gdb GNU gdb (GDB) 7.5 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "--host=i686-host-linux-gnu --target=arm-cortexa8-linux-gnueabihf". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. (gdb) target extended 192.168.5.52:2345 Remote debugging using 192.168.5.52:2345 (gdb) set remote exec-file /opt/milav/qt-mosquitto (gdb) run Starting program: Program received signal SIGILL, Illegal instruction. 0x404df208 in ?? () (gdb) bt #0 0x404df208 in ?? () Cannot access memory at address 0x0 #1 0x404092c0 in ?? () Cannot access memory at address 0x0 #2 0x404092c0 in ?? () Cannot access memory at address 0x0 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb)i think you got what you want.
looking forward hearing from you.
@Milav said in segmentation fault:
i think you got what you want
Not really.
Did you build the app in debug mode? -
@Milav said in segmentation fault:
i think you got what you want
Not really.
Did you build the app in debug mode? -
Hello,
I make a qt application for Embedded Custom Board and when i run the Application it gives segmentation fault.
The application give segmentation fault due to following line.
mosq->subscribe(mosq->getMID(), topic.data(), 1);where mosq is define and declare as follow.
class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); private: qtmosq* mosq = NULL; QStringList subed; QString currentTopic; Ui::MainWindow *ui; -------- -------- -------- };where qtmosq is define as follow..
#include "QObject" #include "mosquittopp.h" using namespace mosqpp; class qtmosq : public QObject, public mosquittopp { Q_OBJECT public: qtmosq(const char *id = NULL, bool clean_session = true) : mosquittopp (id, clean_session) {MID = 0;} ~qtmosq() {} void on_connect(int result) { if (!result) { //subscribe(NULL, "$SYS/#", 2); emit connected(); } else emit connectEnable(); } void on_publish(int id) { MID++; emit messageSent(true); } void on_subscribe(int mid, int qos_count, const int *granted_qos) { if (MID != 0) emit subscribed(); MID++; } .......... .......... .......... signals: void connected(); void messageSent(bool); void messageReceived(QString); void connectEnable(); void subscribed(); };so what is the reason behind for this fault.
The same application are successfully run on Host Linux PC.
I have use same mosquitto library in both the test.
please help me to sort out this problem.
I have send the reference link at where i used above program.
Link :- Ref. Link
Thank you
Milav Soni@Milav said in segmentation fault:
Link :- Ref. Link
Could it be possible that you run such example AS IS, I mean just download/clone the code and try such example without any change.
If you manage to make it work, then you'll have the foundation to start adapting it to whatever you need/desire.In addition, is there any compelling reason not to use the Qt MQTT module?
Have you try any of the Qt MQTT examples?Upvote the answer(s) that helped you solve the issue
Use "Topic Tools" button to mark your post as Solved
Add screenshots via postimage.org
Don't ask support requests via chat/PM. Please use the forum so others can benefit from the solution in the future -
@Milav said in segmentation fault:
Link :- Ref. Link
Could it be possible that you run such example AS IS, I mean just download/clone the code and try such example without any change.
If you manage to make it work, then you'll have the foundation to start adapting it to whatever you need/desire.In addition, is there any compelling reason not to use the Qt MQTT module?
Have you try any of the Qt MQTT examples?@Pablo-J-Rogina said in segmentation fault:
In addition, is there any compelling reason not to use the Qt MQTT module?
Have you try any of the Qt MQTT examples?I use actually qt4.8.7 source for development so QMqtt is not build for this qt version, so that i do not use qmqtt class.
if you have any idea how to run QMqtt in qt 4.8.7 source than please tell me it is so helpful to me.
@Pablo-J-Rogina said in segmentation fault:
Could it be possible that you run such example AS IS, I mean just download/clone the code and try such example without any change.
If you manage to make it work, then you'll have the foundation to start adapting it to whatever you need/desire.i actually tried same as is code for pc development and that is work fine.
but when i cross compiling the code for embedded target board than it gives segmentation error,
the difference between host pc and Embedded target board is only QT source.
Host pc => qmake (qt version 5.4.0 )
Embedded target => qmake (qt version 4.8.7)hope you got my point.
if you have any query please tell me.
and please guys help me to sort out the problem.
i am also try another code for the same , but in that i have also suffer same problem.
Another code link :- link text
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@Pablo-J-Rogina said in segmentation fault:
In addition, is there any compelling reason not to use the Qt MQTT module?
Have you try any of the Qt MQTT examples?I use actually qt4.8.7 source for development so QMqtt is not build for this qt version, so that i do not use qmqtt class.
if you have any idea how to run QMqtt in qt 4.8.7 source than please tell me it is so helpful to me.
@Pablo-J-Rogina said in segmentation fault:
Could it be possible that you run such example AS IS, I mean just download/clone the code and try such example without any change.
If you manage to make it work, then you'll have the foundation to start adapting it to whatever you need/desire.i actually tried same as is code for pc development and that is work fine.
but when i cross compiling the code for embedded target board than it gives segmentation error,
the difference between host pc and Embedded target board is only QT source.
Host pc => qmake (qt version 5.4.0 )
Embedded target => qmake (qt version 4.8.7)hope you got my point.
if you have any query please tell me.
and please guys help me to sort out the problem.
i am also try another code for the same , but in that i have also suffer same problem.
Another code link :- link text
@Milav OK, maybe we should start from the beginning.
Do you cross compile from PC to device?
Does the app crash in same way on host with Qt5?
Is it possible that you're mixing Qt4 and Qt5 on your target device? You can check this using "ldd EXECUTABLE" on your target.
Please do this on your target (in a terminal):file /opt/milav/qt-mosquitto ldd /opt/milav/qt-mosquittoand post the output here.
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@Milav OK, maybe we should start from the beginning.
Do you cross compile from PC to device?
Does the app crash in same way on host with Qt5?
Is it possible that you're mixing Qt4 and Qt5 on your target device? You can check this using "ldd EXECUTABLE" on your target.
Please do this on your target (in a terminal):file /opt/milav/qt-mosquitto ldd /opt/milav/qt-mosquittoand post the output here.
@jsulm said in segmentation fault:
OK, maybe we should start from the beginning.
Okay sure.
@jsulm said in segmentation fault:
Do you cross compile from PC to device?
Yes i cross compile the "qt-mosquitto" application for target (device) from qt creator (that is install on pc).
For cross compilng i have use qmake version 4.8.7.
and qt creator version is "Qt Creator 3.3.0 (opensource)"
and for v
@jsulm said in segmentation fault:
Does the app crash in same way on host with Qt5?
No, the application is not crash in PC.
In pc i have use same code but qmake vwersion is 5.4.0
@jsulm said in segmentation fault:
Is it possible that you're mixing Qt4 and Qt5 on your target device? You can check this using "ldd EXECUTABLE" on your target.
In target i have only qt 4 library and qmake are there.
i think there is no qt 5 component in target device.@jsulm said in segmentation fault:
Please do this on your target (in a terminal):
sorry for this, but i have not ldd command on target device.
if it is necessary than tell i have install and cross compile it for target device.sorry i dont know why this ldd cmd is not there in target device.
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@jsulm said in segmentation fault:
OK, maybe we should start from the beginning.
Okay sure.
@jsulm said in segmentation fault:
Do you cross compile from PC to device?
Yes i cross compile the "qt-mosquitto" application for target (device) from qt creator (that is install on pc).
For cross compilng i have use qmake version 4.8.7.
and qt creator version is "Qt Creator 3.3.0 (opensource)"
and for v
@jsulm said in segmentation fault:
Does the app crash in same way on host with Qt5?
No, the application is not crash in PC.
In pc i have use same code but qmake vwersion is 5.4.0
@jsulm said in segmentation fault:
Is it possible that you're mixing Qt4 and Qt5 on your target device? You can check this using "ldd EXECUTABLE" on your target.
In target i have only qt 4 library and qmake are there.
i think there is no qt 5 component in target device.@jsulm said in segmentation fault:
Please do this on your target (in a terminal):
sorry for this, but i have not ldd command on target device.
if it is necessary than tell i have install and cross compile it for target device.sorry i dont know why this ldd cmd is not there in target device.
@Milav said in segmentation fault:
sorry i dont know why this ldd cmd is not there in target device
This is not unusual. On limited devices manufacturers usually remove everything not needed when using the device.
Is "file" command there? -
@Milav said in segmentation fault:
sorry i dont know why this ldd cmd is not there in target device
This is not unusual. On limited devices manufacturers usually remove everything not needed when using the device.
Is "file" command there?@jsulm said in segmentation fault:
This is not unusual. On limited devices manufacturers usually remove everything not needed when using the device.
Is "file" command there?Okay no problem.
actually "file" cmd also not in target device.
but in desktop pc i have "file" cmd so i execute file cmd with binary application file.
here i have show output of that .
tdp0009@tdp0009-desktop:~$ file qt-mosquitto qt-mosquitto: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-, for GNU/Linux 2.6.32, not strippedi think you got your answer from above result.
