From: Eli Zaretskii <eliz@gnu.org>
Date: Sun, 23 Mar 2025 11:17:06 +0000 (+0200)
Subject: Avoid rare crashes due to "C-g C-g" on TTY frames
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=295c08e955774f69392be9c7302f7898956afd08;p=emacs.git

Avoid rare crashes due to "C-g C-g" on TTY frames

* src/term.c (tty_send_additional_strings): Don't use SBYTES, as
this function could be called in the middle of GC.  (Bug#77205)

(cherry picked from commit 939a2a3c2dd60503c6ebef839b5f05f962d405ce)
---

diff --git a/src/term.c b/src/term.c
index e15b7a0887e..32f3c8c48d6 100644
--- a/src/term.c
+++ b/src/term.c
@@ -184,9 +184,15 @@ tty_send_additional_strings (struct terminal *terminal, Lisp_Object sym)
       Lisp_Object string = XCAR (extra_codes);
       if (STRINGP (string))
         {
-	  fwrite (SDATA (string), 1, SBYTES (string), tty->output);
+	  struct Lisp_String *str = XSTRING (string);
+	  /* Don't use SBYTES, as that is not protected from GC.  */
+	  ptrdiff_t sbytes
+	    = (str->u.s.size_byte < 0
+	       ? str->u.s.size & ~ARRAY_MARK_FLAG
+	       : str->u.s.size_byte);
+	  fwrite (SDATA (string), 1, sbytes, tty->output);
           if (tty->termscript)
-	    fwrite (SDATA (string), 1, SBYTES (string), tty->termscript);
+	    fwrite (SDATA (string), 1, sbytes, tty->termscript);
         }
     }
 }