Avoid crashes when ':eval' deletes our frame

* src/xdisp.c (display_mode_element): Signal an error if
':eval' somehow deletes the frame whose window we are
redisplaying. (Bug#29726)
This commit is contained in:
Eli Zaretskii 2017-12-23 13:59:07 +02:00
parent 9105c9aa34
commit 720ed0b533

View file

@ -23685,6 +23685,14 @@ display_mode_element (struct it *it, int depth, int field_width, int precision,
{
Lisp_Object spec;
spec = safe__eval (true, XCAR (XCDR (elt)));
/* The :eval form could delete the frame stored in the
iterator, which will cause a crash if we try to
access faces and other fields (e.g., FRAME_KBOARD)
on that frame. This is a nonsensical thing to do,
and signaling an error from redisplay might be
dangerous, but we cannot continue with an invalid frame. */
if (!FRAME_LIVE_P (it->f))
signal_error (":eval deleted the frame being displayed", elt);
n += display_mode_element (it, depth, field_width - n,
precision - n, spec, props,
risky);