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Heap errors behavior is dependent on target machine. [message #45539]

Sat, 28 November 2015 14:03

jfranks
Messages: 36
Registered: September 2014
Location: Houston, Texas

Member

Brief Description: Memory heap errors don't happen for development
machine 'A'. However, they do occur for the same
executable image on the embedded target machine
'B'.

Full Description of the issue:

Description of development machine -- i.e., machine 'A'

The development machine is a Dell desktop computer that has an
Intel CORE i5, and a host operating system Windows 7. A virtual
machine was installed using Oracle VM Virtual Box to run a guest
operating system Linux Mint 17.2. Our application development was
done on this virtual machine as a Linux based application using U++
nightly snapshot upp-x11-src-9200.

Description of the embedded target machine -- i.e., machine 'B'

This is proprietary custom hardware that has a touchscreen, custom
keypad entry device, a commercial power supply, commercial single
board computer, and a hard drive. The operating system is the same
as that used on the development machine. The CPU is compatible
to run the executable image produced on the development machine.

Description of the problem we are having with U++ memory diagnostic:

1. We developed and debugged our graphical U++ application on
machine 'A'. All memory heap errors were located and
corrected. The executable image developed on this machine is
compatible for running on machine 'B'.

2. We installed the debug version of our executable image on machine
'B'. Everything runs great except when we exit our application.
The behavior is different on machine 'B' in that there are memory
heap errors, followed by a segfault on X11.

Heap leaks detected!
Segmentation fault

3. We enabled machine 'B' to have development capability and installed
U++ IDE based on upp-x11-src-9200. We did a code checkout into this
machine from our SVN server. We compiled the code. Then we ran the
debug executable built on this machine. The result was the same
as item 2 above.

The debug executable image built on machine 'B' was copied to
machine 'A' and it exhibited a different behavior -- it worked
correctly on exit from the application, i.e., there were no
memory heap errors, nor segfault. That is odd.

Next, we decided to start debugging on machine 'B' in earnest.
We modified our application code and inserted MemoryIgnoreLeaksBegin();
and MemoryIgnoreLeaksEnd(); so as to exclude all of our application
code from leak detection. The result was the same as in item 2 above.

We more aggressively applied the U++ memory ignore function by reworking
the GUI_APP_MAIN macro and explicitly replaced it with the following.

//GUI_APP_MAIN {
void GuiMainFn_();
int main(int argc, const char **argv, const char **envptr)
{
MemoryIgnoreLeaksBegin();
UPP::AppInit__(argc, argv, envptr);
UPP::Ctrl::InitX11(NULL);
UPP::AppExecute__(GuiMainFn_);
UPP::Ctrl::ExitX11();
UPP::AppExit__();
MemoryIgnoreLeaksEnd();
return UPP::GetExitCode();
}

void GuiMainFn_()
{
... our application code starts here ....
}

The results on machine 'B' did not change -- still a memory heap
issue on exit and a segfault. A large log file was produced with
many memory breakpoints.

Next, we compiled a release version of the application on
machine 'B' without any debug flags. Everything works great
because the U++ memory diagnostics are disabled. As we run the
release version, there is nothing that indicates a problem at any
time, even when we exit.

The log file generated from running the debug was over 2400 items.
I've attached a snapshot of the call-stack while in the debugger
for the lowest numbered memory break-point #1.

We are having a difficult time sorting this out and are asking
for help or ideas of where we go from here.

-- Jeff

Attachment: call-stack.jpg
(Size: 83.03KB, Downloaded 341 times)

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