[Bug 45070] New: closing threads causes "wine client error" and kills process when run under winedbg --gdb

https://bugs.winehq.org/show_bug.cgi?id=45070

Bug ID: 45070
           Summary: closing threads causes "wine client error" and kills
                    process when run under winedbg --gdb
           Product: Wine
           Version: 3.6
          Hardware: x86
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: winedbg
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 61208
  --> https://bugs.winehq.org/attachment.cgi?id=61208
test program showing problem

When run under winedbg in gdb mode, closing a thread consistently causes 'wine
client error:30: write: Bad file descriptor', aborting the program.

The basic problem seems to be that gdb will inject breakpoints into dlopen() to
allow hooking that function if desired. Normally this works fine, but this can
also be triggered during thread teardown, i.e. inside of pthread_exit(). In
this case we catch the SIGTRAP, but abort when we try to pass it along to
wineserver, since we've already closed our file handle to the server pipe.

The obvious solution seems to be to block SIGTRAP during thread shutdown.
Attempting this makes the 'bad file descriptor' message go away, but the
process still gets killed prematurely. I haven't figured out why.