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* [PATCH] Cygwin: dsp: Fix hang on close() if another thread calls write().
@ 2023-01-25 10:56 Takashi Yano
  2023-01-25 12:35 ` Corinna Vinschen
  0 siblings, 1 reply; 2+ messages in thread
From: Takashi Yano @ 2023-01-25 10:56 UTC (permalink / raw)
  To: cygwin-patches; +Cc: Takashi Yano

fhandler_dev_dsp (OSS) has a problem that waitforallsent(), which is
called from close(), falls into infinite loop if another thread calls
write() accidentally after close(). This patch fixes the issue.

Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
---
 winsup/cygwin/fhandler/dsp.cc           | 9 +++++++++
 winsup/cygwin/local_includes/fhandler.h | 1 +
 2 files changed, 10 insertions(+)

diff --git a/winsup/cygwin/fhandler/dsp.cc b/winsup/cygwin/fhandler/dsp.cc
index 8798cf876..cfbf6bec7 100644
--- a/winsup/cygwin/fhandler/dsp.cc
+++ b/winsup/cygwin/fhandler/dsp.cc
@@ -1093,6 +1093,8 @@ fhandler_dev_dsp::open (int flags, mode_t)
 
   debug_printf ("ACCMODE=%y audio_in=%d audio_out=%d, err=%d, ret=%d",
 		flags & O_ACCMODE, num_in, num_out, err, ret);
+  if (ret)
+    being_closed = false;
   return ret;
 }
 
@@ -1106,6 +1108,12 @@ fhandler_dev_dsp::_write (const void *ptr, size_t len)
   int len_s = len;
   const char *ptr_s = static_cast <const char *> (ptr);
 
+  if (being_closed)
+    {
+      set_errno (EBADF);
+      return -1;
+    }
+
   if (audio_out_)
     /* nothing to do */;
   else if (IS_WRITE ())
@@ -1207,6 +1215,7 @@ int
 fhandler_dev_dsp::close ()
 {
   debug_printf ("audio_in=%p audio_out=%p", audio_in_, audio_out_);
+  being_closed = true;
   close_audio_in ();
   close_audio_out ();
   return fhandler_base::close ();
diff --git a/winsup/cygwin/local_includes/fhandler.h b/winsup/cygwin/local_includes/fhandler.h
index 5fe979538..e7315ae16 100644
--- a/winsup/cygwin/local_includes/fhandler.h
+++ b/winsup/cygwin/local_includes/fhandler.h
@@ -2758,6 +2758,7 @@ class fhandler_dev_dsp: public fhandler_base
   int audiochannels_;
   Audio_out *audio_out_;
   Audio_in  *audio_in_;
+  bool being_closed;
  public:
   fhandler_dev_dsp ();
   fhandler_dev_dsp *base () const {return (fhandler_dev_dsp *)archetype;}
-- 
2.39.0


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] Cygwin: dsp: Fix hang on close() if another thread calls write().
  2023-01-25 10:56 [PATCH] Cygwin: dsp: Fix hang on close() if another thread calls write() Takashi Yano
@ 2023-01-25 12:35 ` Corinna Vinschen
  0 siblings, 0 replies; 2+ messages in thread
From: Corinna Vinschen @ 2023-01-25 12:35 UTC (permalink / raw)
  To: cygwin-patches

On Jan 25 19:56, Takashi Yano wrote:
> fhandler_dev_dsp (OSS) has a problem that waitforallsent(), which is
> called from close(), falls into infinite loop if another thread calls
> write() accidentally after close(). This patch fixes the issue.

Sounds like a bug in the application to me, but yeah, patch is ok.


Thanks,
Corinna

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2023-01-25 12:35 UTC | newest]

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2023-01-25 10:56 [PATCH] Cygwin: dsp: Fix hang on close() if another thread calls write() Takashi Yano
2023-01-25 12:35 ` Corinna Vinschen

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