Re: cygwin application hangs on closing console

[Takashi Yano <takashi.yano@nifty.ne.jp>]

On Wed, 15 May 2024 17:48:49 +0200
Johannes Khoshnazar-Thoma wrote:
> Hi again,
> 
> Am 15.05.24 um 17:37 schrieb Johannes Khoshnazar-Thoma:
> > Hi again,
> >
> > Am 23.04.24 um 12:26 schrieb Takashi Yano:
> >>>> Thanks for the report. Could you please test cygwin1.dll 3.5.3-1
> >>>> wihch is the latest cygwin release?
> >>>>
> >
> > We retried the tests with cygwin1.dll 3.5.3-1 and it looks like
> > the issue is still there. Here's an excerpt from the gdb debug
> > session:
> >
> Sorry somehow the formatting got messed up I try again:

Thanks for testing and the additional information.

> (gdb) info thread
>    Id   Target Id         Frame
> * 1    Thread 0x11cc     0x00007ffe579d5ea4 in ntdll!ZwWaitForSingleObject () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
>    2    Thread 0x8ec      0x00007ffe579d5ee4 in ntdll!ZwReadFile () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
>    3    Thread 0x55c      0x00007ffe579d5ea4 in ntdll!ZwWaitForSingleObject () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
>    4    Thread 0x131c     0x00007ffe579d95f4 in ntdll!ZwWaitForWorkViaWorkerFactory () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
>    5    Thread 0x9b8      0x00007ffe579d95f4 in ntdll!ZwWaitForWorkViaWorkerFactory () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
> (gdb) thread 1
> [Switching to thread 1 (Thread 0x11cc)]
> #0  0x00007ffe579d5ea4 in ntdll!ZwWaitForSingleObject () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
> (gdb) bt
> #0  0x00007ffe579d5ea4 in ntdll!ZwWaitForSingleObject () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
> #1  0x00007ffe54156d1f in WaitForSingleObjectEx () from C:\src\dlls-syms\KERNELBASE.dll\660F5EEC21e000\KERNELBASE.dll
> #2  0x00007ffe4a2033a0 in fhandler_console::close (this=0x800009030) at /usr/src/debug/cygwin-3.5.3-1/winsup/cygwin/fhandler/console.cc:1914

Line 1914 of fhandler/console.cc is:
      WaitForSingleObject (thread_sync_event, INFINITE);

This waits termination of cons_master_thread(). However, it does not seem
that the cons_master_thread exists in thread list obove. If the thread was
terminated normally, thread_sync_event should has been set.

> #0  0x00007ffe579d5ea4 in ntdll!ZwWaitForSingleObject () from C:\src\dlls-syms\ntdll.dll\6502806A1cf000\ntdll.dll
> (gdb) up
> #1  0x00007ffe54156d1f in WaitForSingleObjectEx () from C:\src\dlls-syms\KERNELBASE.dll\660F5EEC21e000\KERNELBASE.dll
> (gdb)
> #2  0x00007ffe4a2033a0 in fhandler_console::close (this=0x800009030) at /usr/src/debug/cygwin-3.5.3-1/winsup/cygwin/fhandler/console.cc:1914
> 1914    in /usr/src/debug/cygwin-3.5.3-1/winsup/cygwin/fhandler/console.cc
> (gdb) p thread_sync_event
> $6 = (HANDLE) 0x1510
> (gdb) p name
> $7 = "cygcons.thread_sync.0", '\000' <repeats 19 times>, "r", '\000' <repeats 183 times>...
> (gdb) p con.owner
> No symbol "con" in current context.
> (gdb) p master_thread_started
> $8 = true
> (gdb) p unit
> $9 = 0
> (gdb) p shared_console_info
> $10 = {0x1a0030000, 0x0 <repeats 64 times>}
> (gdb)

fhandler_console::close() was called twice? Or master thread had crashed
without setting thread_sync_event?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>