[Bug 49860] New: Dungeons & Dragons Online 64bit client fails to start in wine-5.16 and 5.17

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49860

Bug ID: 49860
           Summary: Dungeons & Dragons Online 64bit client fails to start
                    in wine-5.16 and 5.17
           Product: Wine
           Version: 5.15
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ntdll
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 68202
  --> https://bugs.winehq.org/attachment.cgi?id=68202
error stacktrace

The 64bit client of DDO fails to start in wine 5.16 and 5.17.
The client starts and shows a black screen for a second, and then crashes with:
00e8:err:seh:NtRaiseException Unhandled exception code c0000005 flags 0 addr
0x6760a76d
(see attached trace)

Bisecting shows the bad commit is a686759f1d7aee67b5786b72e81a4e4fcf3f3c02

If I revert that commit on top of the current master, the client works again.

Since they also have a 32bit legacy client which still works, I would guess
that the changes in dlls/ntdll/unix/signal_x86_64.c cause some different
behaviour than the old implementation did.

For DDO the workaround would be to just use the 32bit client, but there may be
other programs affected by this change.