How to resolve below type of crash issue for QT/QML Application on linux ?

Qt embedded developer

@jsulm As per my dmesg i have found that my displaydatacont thread cause the crash

Qt embedded developer

@sierdzio I have found through the debug log that

My multi threading application log make me confuse
due to which function application get crash because

the function which run 100 time right

for non zero values of parameter make crash after 101th time.

i got confused because i don't know

application get crash due to race condition. or due to other reason.

i want to know how to identify its race condition through logs ?

sierdzio

We've given you plenty of options already. For thread issues you can use - you guessed it - thread sanitizer. You don't have to run it on your remote device, run it locally on your PC and it will detect issues (same with asan).

If you absolutely have to do it on device, connect to it remotely with a debugger. Detecting a race through log files will be extremely hard, especially since the log runs on a single thread (so basically it will NOT show you exactly what happens in parallel. Log gets serialized when it's written).

Qt embedded developer

@sierdzio

I have found below log through gdb .

But not know what is reason for crash from below log ?

could not parse string to float
could not parse string to integer NA
could not parse string to float
[New Thread 0x7fff33ff7640 (LWP 98477)]
[New Thread 0x7fff47fff640 (LWP 98478)]
[Thread 0x7fff33ff7640 (LWP 98477) exited]
[Thread 0x7fff47fff640 (LWP 98478) exited]
could not parse string to integer na
could not parse string to integer na
could not parse string to integer na
could not parse string to integer na
could not parse string to integer na
could not parse string to integer na
could not parse string to integer na
could not parse string to float
could not parse string to float
could not parse string to float
could not parse string to integer NA
could not parse string to integer NA
could not parse string to integer NA
could not parse string to integer NA
could not parse string to integer NA
could not parse string to integer NA
could not parse string to float
could not parse string to integer NA
could not parse string to float

Thread 1 "APPcheck" received signal SIGSEGV, Segmentation fault.
0x00007ffff7ee1f14 in std::__cxx11::list<int, std::allocator<int> >::unique() () from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so
(gdb) bt
#0 0x00007ffff7ee1f14 in std::__cxx11::list<int, std::allocator<int> >::unique() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so
#1 0x00007ffff7ee0f6c in cdi::CDIProbe::getProbeErrorListabi:cxx11 ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so
#2 0x000055555563d371 in StatusController::slotPollingRequested (
this=0x555555e51310)
at ../../CDIBMS/CDIBMSComponents/controllers/statuscontroller.cpp:558
#3 0x000055555565b283 in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, bool (StatusController::)()>::call(bool (StatusController::)(), StatusController*, void**) (
f=(bool (StatusController::)(StatusController * const)) 0x55555563ab3e StatusController::slotPollingRequested(), o=0x555555e51310, arg=0x7fffffffd590)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:152
#4 0x000055555565adf0 in QtPrivate::FunctionPointer<bool (StatusController::)()>::call<QtPrivate::List<>, void>(bool (StatusController::)(), StatusController, void**) (
f=(bool (StatusController::*)(StatusController * const)) 0x55555563ab3e StatusController::slotPollingRequested(), o=0x555555e51310, arg=0x7fffffffd590)
--Type <RET> for more, q to quit, c to continue without paging--

#5 0x000055555565a2b8 in QtPrivate::QSlotObject<bool (StatusController::)(), QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase, QObject*, void**, bool*) (which=1, this_=0x555555f8ed00, r=0x555555e51310, a=0x7fffffffd590, ret=0x0)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:418
#6 0x00007ffff42d7860 in void doActivate<false>(QObject*, int, void**) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#7 0x00005555557b3ca3 in DisplayDataController::sigPollRequest (this=0x555556002600) at moc_displaydatacontroller.cpp:307
#8 0x00005555558bed2c in DisplayDataController::slotPollTimeout (this=0x555556002600)
at ../../CDIBMS/CDIBMSComponents/controllers/displaydatacontroller.cpp:1554
#9 0x00005555558d1aaf in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, void (DisplayDataController::)()>::call(void (DisplayDataController::)(), DisplayDataController*, void**) (
f=(void (DisplayDataController::)(DisplayDataController * const)) 0x5555558bed10 DisplayDataController::slotPollTimeout(), o=0x555556002600,
arg=0x7fffffffd810) at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:152
#10 0x00005555558d176d in QtPrivate::FunctionPointer<void (DisplayDataController::)()>::call<QtPrivate::List<>, void>(void (DisplayDataController::)(), DisplayDataController, void**) (
f=(void (DisplayDataController::)(DisplayDataController * const)) 0x5555558bed10 DisplayDataController::slotPollTimeout(), o=0x555556002600,
arg=0x7fffffffd810) at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:185
#11 0x00005555558d1158 in QtPrivate::QSlotObject<void (DisplayDataController::)(), QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) (which=1, this_=0x555555eed0e0, r=0x555556002600, a=0x7fffffffd810, ret=0x0)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:418
#12 0x00007ffff42d7860 in void doActivate<false>(QObject*, int, void**) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#13 0x00007ffff42dc397 in QTimer::timeout(QTimer::QPrivateSignal) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#14 0x00007ffff42dc668 in QTimer::timerEvent(QTimerEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#15 0x00007ffff42ce59b in QObject::event(QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#16 0x00007ffff676354c in QApplicationPrivate::notify_helper(QObject*, QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Widgets.so.5
#17 0x00007ffff676a010 in QApplication::notify(QObject*, QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Widgets.so.5
#18 0x00007ffff429ece8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#19 0x00007ffff42f9e69 in QTimerInfoList::activateTimers() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#20 0x00007ffff42fa679 in idleTimerSourceDispatch(_GSource*, int ()(void), void*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#21 0x00007ffff571bd3b in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007ffff57706c8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007ffff57193e3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
--Type <RET> for more, q to quit, c to continue without paging--c
#24 0x00007ffff42fa9ac in QEventDispatcherGlib::processEvents(QFlagsQEventLoop::ProcessEventsFlag) () from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#25 0x00007ffff429d6da in QEventLoop::exec(QFlagsQEventLoop::ProcessEventsFlag) () from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#26 0x00007ffff42a66c3 in QCoreApplication::exec() () from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#27 0x00005555555b8bca in main (argc=1, argv=0x7fffffffdfe8) at ../../CDIBMS/APPcheck/src/main.cpp:146
(gdb)
(gdb)
(gdb) thread apply all bt

Thread 57 (Thread 0x7fff347f8640 (LWP 94925) "queue9:src"):
Couldn't get registers: No such process.
(gdb) bt
#0 0x00007ffff7ee1f14 in std::__cxx11::list<int, std::allocator<int> >::unique() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so
#1 0x00007ffff7ee0f6c in cdi::CDIProbe::getProbeErrorListabi:cxx11 ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so
#2 0x000055555563d371 in StatusController::slotPollingRequested (
this=0x555555e51310)
at ../../CDIBMS/CDIBMSComponents/controllers/statuscontroller.cpp:558
#3 0x000055555565b283 in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, bool (StatusController::)()>::call(bool (StatusController::)(), StatusController*, void**) (
f=(bool (StatusController::)(StatusController * const)) 0x55555563ab3e StatusController::slotPollingRequested(), o=0x555555e51310, arg=0x7fffffffd590)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:152
#4 0x000055555565adf0 in QtPrivate::FunctionPointer<bool (StatusController::)()>::call<QtPrivate::List<>, void>(bool (StatusController::)(), StatusController, void**) (
f=(bool (StatusController::*)(StatusController * const)) 0x55555563ab3e StatusController::slotPollingRequested(), o=0x555555e51310, arg=0x7fffffffd590)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:185--Type <RET> for more, q to quit, c to continue without paging--

#5 0x000055555565a2b8 in QtPrivate::QSlotObject<bool (StatusController::)(), QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase, QObject*, void**, bool*) (which=1, this_=0x555555f8ed00, r=0x555555e51310, a=0x7fffffffd590,
ret=0x0)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:418
#6 0x00007ffff42d7860 in void doActivate<false>(QObject*, int, void**) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#7 0x00005555557b3ca3 in DisplayDataController::sigPollRequest (
this=0x555556002600) at moc_displaydatacontroller.cpp:307
#8 0x00005555558bed2c in DisplayDataController::slotPollTimeout (
this=0x555556002600)
at ../../CDIBMS/CDIBMSComponents/controllers/displaydatacontroller.cpp:1554
#9 0x00005555558d1aaf in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, void (DisplayDataController::)()>::call(void (DisplayDataController::)(), DisplayDataController*, void**) (
f=(void (DisplayDataController::)(DisplayDataController * const)) 0x5555558bed10 DisplayDataController::slotPollTimeout(), o=0x555556002600,
arg=0x7fffffffd810)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:152
--Type <RET> for more, q to quit, c to continue without paging--
#10 0x00005555558d176d in QtPrivate::FunctionPointer<void (DisplayDataController::)()>::call<QtPrivate::List<>, void>(void (DisplayDataController::)(), DisplayDataController, void**) (
f=(void (DisplayDataController::)(DisplayDataController * const)) 0x5555558bed10 DisplayDataController::slotPollTimeout(), o=0x555556002600,
arg=0x7fffffffd810)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:185
#11 0x00005555558d1158 in QtPrivate::QSlotObject<void (DisplayDataController::)(), QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) (which=1, this_=0x555555eed0e0, r=0x555556002600,
a=0x7fffffffd810, ret=0x0)
at /home/terumo/Qt5.15.8/5.15.8/gcc_64/include/QtCore/qobjectdefs_impl.h:418
#12 0x00007ffff42d7860 in void doActivate<false>(QObject*, int, void**) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#13 0x00007ffff42dc397 in QTimer::timeout(QTimer::QPrivateSignal) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#14 0x00007ffff42dc668 in QTimer::timerEvent(QTimerEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
--Type <RET> for more, q to quit, c to continue without paging--
#15 0x00007ffff42ce59b in QObject::event(QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#16 0x00007ffff676354c in QApplicationPrivate::notify_helper(QObject*, QEvent*)
()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Widgets.so.5
#17 0x00007ffff676a010 in QApplication::notify(QObject*, QEvent*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Widgets.so.5
#18 0x00007ffff429ece8 in QCoreApplication::notifyInternal2(QObject*, QEvent*)
()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#19 0x00007ffff42f9e69 in QTimerInfoList::activateTimers() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#20 0x00007ffff42fa679 in idleTimerSourceDispatch(_GSource*, int ()(void), void*) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#21 0x00007ffff571bd3b in g_main_context_dispatch ()
from /lib/x86_64-linux-gnu/libglib-2.0.so.0
--Type <RET> for more, q to quit, c to continue without paging--
#22 0x00007ffff57706c8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007ffff57193e3 in g_main_context_iteration ()
from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007ffff42fa9ac in QEventDispatcherGlib::processEvents(QFlagsQEventLoop::ProcessEventsFlag) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#25 0x00007ffff429d6da in QEventLoop::exec(QFlagsQEventLoop::ProcessEventsFlag) ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#26 0x00007ffff42a66c3 in QCoreApplication::exec() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libQt5Core.so.5
#27 0x00005555555b8bca in main (argc=1, argv=0x7fffffffdfe8)
at ../../CDIBMS/APPcheck/src/main.cpp:146
(gdb) thread
[Current thread is 1 (Thread 0x7ffff47ff000 (LWP 94854))]
(gdb) thread all
Invalid thread ID: all
(gdb)

jsulm

@Qt-embedded-developer said in How to resolve below type of crash issue for QT/QML Application on linux ?:

#2 0x000055555563d371 in StatusController::slotPollingRequested (

Look what is inside StatusController::slotPollingRequested in ../../CDIBMS/CDIBMSComponents/controllers/statuscontroller.cpp line 558 ...

Qt embedded developer

@jsulm

On that line i have put for loop.

for (errorcode = lConnProbe->getProbeErrorList()->begin(); errorcode != lConnProbe->getProbeErrorList()->end(); ++errorcode)

that code is like below :


                        list<int>::iterator errorcode;
                        for (errorcode = lConnProbe->getProbeErrorList()->begin(); errorcode != lConnProbe->getProbeErrorList()->end(); ++errorcode)
                        {
                            switch(*errorcode)
                            {

jsulm

@Qt-embedded-developer Now take a look at the stack trace entry one up:

#1 0x00007ffff7ee0f6c in cdi::CDIProbe::getProbeErrorListabi:cxx11 ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so

So, the error come from getProbeErrorList(). And the top entry from stack trace is:

#0 0x00007ffff7ee1f14 in std::__cxx11::list<int, std::allocator<int> >::unique() ()
from /home/terumo/.Downloads/APPCHECK_24March2023_USB_BUILD_WithDebug/CDI1500DisplayApp/lib/libCDIDisplayData.so

This is what you need to check next.

Qt embedded developer

@jsulm For that i have implemented below code :

std::list<int>* CDIProbe::getProbeErrorList()
{
pInfo.probeErrorCodes.sort();
pInfo.probeErrorCodes.unique();
return &pInfo.probeErrorCodes;
}

jsulm

@Qt-embedded-developer And as you can clearly see from the stack trace unique() is causing the crash.
If you're using multi-threading and accessing same data from different threads: do you synchronise the access to shared data?

Qt embedded developer

@jsulm Thanks we have resolve this type of crash by using mutex.

And yes we use same this error list from 2 thread. and that's why this code cause the crash.

Qt embedded developer

This post is deleted!