bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

[Eli Zaretskii]

[Please keep the bug address on the CC list.]

> From: Sean McAfee <smcafee@sungevity.com>
> Date: Mon, 16 Nov 2015 11:42:19 -0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> > I cannot reproduce this.  Emacs doesn't become unresponsive when I try
> > this recipe.
> >
> > When this happens, can you attach a debugger and show both a C
> > backtrace and a Lisp backtrace?
> 
> Here's the C backtrace:
> 
> (gdb) bt
> #0  0x00007f15b2756e79 in __pselect (nfds=nfds@entry=14, 
>     readfds=readfds@entry=0x7ffe77cde630, 
>     writefds=writefds@entry=0x7ffe77cde6b0, exceptfds=exceptfds@entry=0x0, 
>     timeout=<optimized out>, timeout@entry=0x7ffe77cdec40, 
>     sigmask=sigmask@entry=0x0) at ../sysdeps/unix/sysv/linux/pselect.c:77
> #1  0x00000000005cedcd in xg_select (fds_lim=14, 
>     rfds=rfds@entry=0x7ffe77cdee00, wfds=wfds@entry=0x7ffe77cdee80, 
>     efds=efds@entry=0x0, timeout=timeout@entry=0x7ffe77cdec40, 
>     sigmask=sigmask@entry=0x0) at xgselect.c:113
> #2  0x0000000000599361 in wait_reading_process_output (
>     time_limit=time_limit@entry=0, nsecs=nsecs@entry=0, 
>     read_kbd=read_kbd@entry=-1, do_display=true, 
>     wait_for_cell=wait_for_cell@entry=0, wait_proc=wait_proc@entry=0x0, 
>     just_wait_proc=just_wait_proc@entry=0) at process.c:4842
> #3  0x00000000004f4885 in kbd_buffer_get_event (end_time=0x0, 
>     used_mouse_menu=0x7ffe77cdf6eb, kbp=<synthetic pointer>) at 
> keyboard.c:3805

This says that Emacs waits for you to type something.  I don't see any
signs of lack of responsiveness here.

Are you sure you see no question in the minibuffer at this point?