Cygwin: signal: Do not handle signal when __SIGFLUSHFAST is sent

The commit a22a0ad was not exactly the correct thing. Even with the patch, some hangs still happen. This patch overrides the previous commit to fix these hangs. Addresses: https://cygwin.com/pipermail/cygwin/2024-December/256987.html Fixes: a22a0ad ("Cygwin: signal: Do not handle signal when __SIGFLUSHFAST is sent") Reported-by: Jeremy Drake <[email protected]> Reviewed-by: Signed-off-by: Takashi Yano <[email protected]>
msys2 · Jan 18, 2025 · 0f82cd1 · 0f82cd1
1 parent 3506dba
commit 0f82cd1
Showing 1 changed file with 27 additions and 6 deletions.
diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
@@ -751,8 +751,19 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
       res = WriteFile (sendsig, leader, packsize, &nb, NULL);
       if (!res || packsize == nb)
 	break;
-      if (cygwait (NULL, 10, cw_sig_eintr) == WAIT_SIGNALED)
-	_my_tls.call_signal_handler ();
+      if (pack.si.si_signo == __SIGFLUSHFAST)
+	Sleep (10);
+      else /* Handle signals */
+	do
+	  {
+	    DWORD rc = WaitForSingleObject (_my_tls.get_signal_arrived (), 10);
+	    if (rc == WAIT_OBJECT_0)
+	      {
+		_my_tls.call_signal_handler ();
+		continue;
+	      }
+	  }
+	while (false);
       res = 0;
     }
 
@@ -785,7 +796,20 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
   if (wait_for_completion)
     {
       sigproc_printf ("Waiting for pack.wakeup %p", pack.wakeup);
-      rc = cygwait (pack.wakeup, WSSC);
+      if (pack.si.si_signo == __SIGFLUSHFAST)
+	rc = WaitForSingleObject (pack.wakeup, WSSC);
+      else /* Handle signals */
+	do
+	  {
+	    HANDLE w[2] = {pack.wakeup, _my_tls.get_signal_arrived ()};
+	    rc = WaitForMultipleObjects (2, w, FALSE, WSSC);
+	    if (rc == WAIT_OBJECT_0 + 1) /* signal arrived */
+	      {
+		_my_tls.call_signal_handler ();
+		continue;
+	      }
+	  }
+	while (false);
       ForceCloseHandle (pack.wakeup);
     }
   else
@@ -806,9 +830,6 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
       rc = -1;
     }
 
-  if (wait_for_completion && si.si_signo != __SIGFLUSHFAST)
-    _my_tls.call_signal_handler ();
-
 out:
   if (communing && rc)
     {