Subject: Infinite loop noticed on Emacs in OpenBSD

From: Manuel Giraud <[email-masked]>
Date: Thu, 09 Nov 2017 16:06:22 +0100

Hi,

Here is a patch against HEAD to avoid the hang in infinite loop. The
'x-selection-timeout' pause will still be there even with this patch.

My understandings:

On OpenBSD, most of the time, the function
"xselect.c/x_get_foreign_selection" won't get a SelectNotify with
(SECONDARY, TEXT) as arguments (that I did not understand and it might
never happen on other oses).

But then, while waiting at most 'x-selection-timeout' into
"process.c/wait_reading_process_output" the 'now' variable won't have a
chance of being invalidated or updated and that is what cause the
infinite loop.

Someone more knowledgeable of "process.c/wait_reading_process_output"
might have a better solution to this problem.

diff --git a/src/process.c b/src/process.c
index fc46e74332..25bd28a82b 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5115,8 +5115,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
       /* Exit if already run out.  */
       if (wait == TIMEOUT)
 	{
-	  if (!timespec_valid_p (now))
-	    now = current_timespec ();
+	  now = current_timespec ();
 	  if (timespec_cmp (end_time, now) <= 0)
 	    break;
 	  timeout = timespec_sub (end_time, now);
-- 
Manuel Giraud