On Thursday 13 February 2025 14:16:06 Martin Storsjö wrote: > On Fri, 7 Feb 2025, Pali Rohár wrote: > > > This will report runtime error if _CRT_INIT(DLL_PROCESS_DETACH) is called > > by the current thread from some atexit_table hook. > > Btw, I forgot to ask; how would one practically do in order to trigger this > case? I know it's a kinda pathological case that one ideally wouldn't ever > hit, but I wonder if you even know of a theoretical case. I guess one case > is an atexit function which explicitly references the _CRT_INIT symbol? Or > if an atexit function tries to FreeLibrary() on the same DLL that it belongs > to, or something like that? Something else? > > // Martin
It is edge case and I have just imitated logic which is doing visual c++ startup/shutdown code. I thought that this code can catch stupid/basic issues related to single threaded application when some startup or shutdown hook would call _CRT_INIT() function with DLL_PROCESS_DETACH or DLL_PROCESS_ATTACH. But not, after reading your comment and looking at the code again, now I see that this guard does: - NOT detect _CRT_INIT(DLL_PROCESS_DETACH) call from startup hook - NOT detect _CRT_INIT(DLL_PROCESS_DETACH) call from atexit hook What it can theoretically detect is that during FreeLibrary() call when _CRT_INIT(DLL_PROCESS_DETACH) is being executed, some other running thread executes _CRT_INIT(DLL_PROCESS_DETACH) in parallel. In this case while loop with InterlockedCompareExchangePointer would wait in Sleep(1000) until the other thread release __native_startup_lock and then would call _amsg_exit(31) because __native_startup_state would not be __initialized anymore. _______________________________________________ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
