From 059184e645037c947528ef4d8d512f6997613be2 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 17 Sep 2017 22:01:56 -0700 Subject: [PATCH] Avoid crash with C-g C-g in GC Problem reported by Richard Stallman (Bug#17406). Based on fix suggested by Eli Zaretskii (Bug#28279#16). * src/term.c (tty_send_additional_strings): Use only safe accessors, to avoid crash when C-g C-g in GC. --- src/term.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/term.c b/src/term.c index a2ae8c2c6f0..065bce45d3c 100644 --- a/src/term.c +++ b/src/term.c @@ -155,12 +155,16 @@ tty_ring_bell (struct frame *f) static void tty_send_additional_strings (struct terminal *terminal, Lisp_Object sym) { - Lisp_Object lisp_terminal; - Lisp_Object extra_codes; + /* Use only accessors like CDR_SAFE and assq_no_quit to avoid any + form of quitting or signaling an error, since this function can + run as part of the "emergency escape" procedure invoked in the + middle of GC, where quitting means crashing (Bug#17406). */ + if (! terminal->name) + return; struct tty_display_info *tty = terminal->display_info.tty; - XSETTERMINAL (lisp_terminal, terminal); - for (extra_codes = Fterminal_parameter (lisp_terminal, sym); + for (Lisp_Object extra_codes + = CDR_SAFE (assq_no_quit (sym, terminal->param_alist)); CONSP (extra_codes); extra_codes = XCDR (extra_codes)) { -- 2.39.2