[Bug 40714] process_attach is executed too early for forwarded exports ( Oblivon Script Extender cannot load under wine-staging)

[wine-bugs at winehq.org]

https://bugs.winehq.org/show_bug.cgi?id=40714

Sebastian Lackner <sebastian at fds-team.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|-unknown                    |loader
     Ever confirmed|0                           |1
            Summary|Oblivon Script Extender     |process_attach is executed
                   |cannot load under           |too early for forwarded
                   |wine-staging                |exports (Oblivon Script
                   |                            |Extender cannot load under
                   |                            |wine-staging)
            Product|Wine-staging                |Wine
             Status|UNCONFIRMED                 |NEW

--- Comment #10 from Sebastian Lackner <sebastian at fds-team.de> ---
I do not have a proposed patch yet, but I'm going to post my analysis here to
make sure it doesn't get lost in the meantime. As it turns out this is not
really a Wine Staging regression, its a loader issue which occurs under
specific circumstances.

Explanation of what is happening:

* OBSE starts the main process in suspended mode.

* Main process has finished process initialization and calls the
init_process_done wineserver call. A signal is sent to suspend the thread as
soon as possible.

* Main process calls fixup_imports, which in turn imports additional dlls
(import_dll). find_forwarded_export gets called and runs find_forwarded_export.
Unfortunately, this immediately calls process_attach, although the signals are
still blocked (!)

* Main process performs gdi32 font initialization (although signals are
blocked). When performing the select wineserver call to wait on the font mutex,
this request is never fulfilled. Please note that the thread is not properly
suspended though, the wineserver has no suspend context for example.

* OBSE sends APCs to allocate memory and start a new thread. Those APCs are
processed by the main process which is still stuck in the select call.

* The newly created thread tries to run other gdi32 functions (although the
font initialization is not done yet).

In the development version of wine, the new thread will initialize the fonts
itself, and OBSE will magically work although things are going terribly wrong
in the background. In Wine Staging however, a run-once section is used to
control initialization of the freetype. This will lead to a deadlock because
the main thread is still stuck in the middle of the initialization, and the new
thread will not attempt to run initialization itself.

The real problem however is not a Wine Staging issue, but instead that font
initialization (or in general process_attach) is called too early for forwarded
imports.

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