Fork#39268: g++ -O1 produces crashing code when accessing dlls via LoadLibrary()/GetProcAddress()/reinterpret_cast
Open Date: 2019-05-30 18:26
Last Update: 2019-06-03 12:48
URL for this Ticket:
https://osdn.net//projects/mingw/ticket/39268
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Last Changes/Comment on this Ticket:
2019-06-03 12:48 Updated by: keith
Comment:
Reply To comer352l
The code is about accessing SAE-J2534-compliant dlls.
SAE-J2534 specifies an unified interface for accessing different automotive
hardware (interfaces for diagnostic purposes, firmware flashing etc.) via a
proprietary dlls. The spec defines function prototypes, arguments and
return values and the behavior of the functions, the implementation is up
to the equipment manufaturers. It also defines a method to register/find
J2534-compliant dlls using the Windows registry. See http://
www.drewtech.com/support/passthru.html
Sure, but I don't see any specific requirements specification for C++ bindings
... in particular, no requirement for a selectLibrary() method.
That's why the DLL association needs to be changed "on the fly".
By "on the fly", I mean ad-hoc, possibly any number of times after the class
instance has been created. I understand the need to support multiple
arbitrarily named DLLs, but surely any one class instance would need to
establish only one DLL association? Certainly, that's how I would implement it
... a distinct class instance for each distinct DLL association, with the DLL
name, (or a registry selector for that name), passed as argument to the
constructor, and no method tempting a subsequent (potentially harmful) change.
But that's just my opinion; it's your application, so your choice.
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Ticket Status:
Reporter: comer352l
Owner: (None)
Type: Issues
Status: Closed
Priority: 5 - Medium
MileStone: (None)
Component: (None)
Severity: 5 - Medium
Resolution: Invalid
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Ticket details:
I'm investigating the following crash, which occurs when accessing a dll via
LoadLibrary(), getProcAddress(), reinterpret_cast:
Problem signature:
Problem Event Name: BEX
Application Name: test.exe
...
Fault Module Name: StackHash_0a9e
...
Exception Offset: 0028fe9c
Exception Code: c0000005
Exception Data: badc0de1
...
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789
The code only crashes if it is compiled with -O1 (-O2, ...).
Moving around pieces of the code seems to fix the issue.
I was finally able to create some reduced example code with working / non
working variants (attachment follows).
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