GNU bug report logs - #18528
24.3.93; Crash during restoration of frameset from desktop

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Package: emacs;

Reported by: Eli Zaretskii <eliz <at> gnu.org>

Date: Mon, 22 Sep 2014 15:24:02 UTC

Severity: normal

Found in version 24.3.93

Done: Eli Zaretskii <eliz <at> gnu.org>

Bug is archived. No further changes may be made.

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Eli Zaretskii <eliz <at> gnu.org>
Subject: bug#18528: closed (Re: bug#18528: 24.3.93; Crash during
 restoration of frameset from desktop)
Date: Wed, 24 Sep 2014 07:35:03 +0000
[Message part 1 (text/plain, inline)]
Your bug report

#18528: 24.3.93; Crash during restoration of frameset from desktop

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 18528 <at> debbugs.gnu.org.

-- 
18528: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18528
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems
[Message part 2 (message/rfc822, inline)]
From: Eli Zaretskii <eliz <at> gnu.org>
To: 18528-done <at> debbugs.gnu.org
Subject: Re: bug#18528: 24.3.93;
 Crash during restoration of frameset from desktop
Date: Wed, 24 Sep 2014 10:33:59 +0300
I've committed the patches to fix this bug in r11751 on the emacs-24
branch, and I'm closing the bug.

[Message part 3 (message/rfc822, inline)]
From: Eli Zaretskii <eliz <at> gnu.org>
To: bug-gnu-emacs <at> gnu.org
Cc: martin rudalics <rudalics <at> gmx.at>
Subject: 24.3.93; Crash during restoration of frameset from desktop
Date: Mon, 22 Sep 2014 18:23:07 +0300
Today I started Emacs 24.3.93, and it crashed near the end of
restoring the last session from .emacs.desktop, when it was
re-creating the frames recorded in that file.  Here's the backtrace:

  Program received signal SIGSEGV, Segmentation fault.
  _malloc_internal_nolock (size=size <at> entry=4294967285) at gmalloc.c:897
  897     gmalloc.c: No such file or directory.
  (gdb) bt 10
  #0  _malloc_internal_nolock (size=size <at> entry=4294967285) at gmalloc.c:897
  #1  0x011eff12 in _realloc_internal_nolock (ptr=0x3e89600, size=4294967285)
      at gmalloc.c:1441
  #2  0x01123f22 in xrealloc (block=0x3e89600, size=4294967285) at alloc.c:717
  #3  0x0100a25e in adjust_decode_mode_spec_buffer (f=<optimized out>)
      at dispnew.c:2106
  #4  adjust_frame_glyphs (f=f <at> entry=0x418ca80) at dispnew.c:1756
  #5  0x0100abd0 in change_frame_size_1 (f=0x418ca80,
      new_width=<optimized out>, new_height=<optimized out>,
      pretend=pretend <at> entry=false, delay=delay <at> entry=false,
      safe=safe <at> entry=false, pixelwise=pixelwise <at> entry=true) at dispnew.c:5596
  #6  0x0100cc89 in change_frame_size (pixelwise=true, safe=<optimized out>,
      delay=false, pretend=false, new_height=<optimized out>,
      new_width=<optimized out>, f=<optimized out>) at dispnew.c:5471
  #7  do_pending_window_change (safe=safe <at> entry=false) at dispnew.c:5432
  #8  0x0100e9e8 in Fset_frame_size (frame=frame <at> entry=104658605, width=2880,
      height=3740, pixelwise=65550402) at frame.c:2645
  #9  0x010126ad in x_set_frame_parameters (f=f <at> entry=0x63cf6a8,
      alist=<optimized out>) at frame.c:3002
  (More stack frames follow...)
  (gdb) frame 4
  #4  adjust_frame_glyphs (f=f <at> entry=0x418ca80) at dispnew.c:1756
  1756    in dispnew.c
  (gdb) p/x f
  $5 = 0x418ca80
  (gdb) p f->text_cols
  $6 = -3  <<<<<<<<<<<<<<<<<<<

As you can see, the text_cols member is negative.  This is the
immediate cause of the crash, because adjust_decode_mode_spec_buffer
does this:

  static void
  adjust_decode_mode_spec_buffer (struct frame *f)
  {
    f->decode_mode_spec_buffer = xrealloc (f->decode_mode_spec_buffer,
					   FRAME_MESSAGE_BUF_SIZE (f) + 1);
  }

and FRAME_MESSAGE_BUF_SIZE is defined like this:

  #define FRAME_MESSAGE_BUF_SIZE(f) (((int) FRAME_COLS (f)) * 4)

So we pass a negative value to xrealloc, which interprets it as a very
large positive value, with predictable results.

Some digging into this reveals the following:

  . The negative values come from w32term.c, around line 4770, where
    they are derived from the value returned by GetClientRect.
    Evidently, it sometimes returns a (0, 0, 0, 0) rectangle for the
    frame dimensions, from which we then subtract the dimensions of
    frame decorations, like scroll bar etc., and call
    change_frame_size.  (We also don't check errors returned by
    GetClientRect.)

  . change_frame_size internally validates the requested dimensions,
    and doesn't allow them to become too small.  But it does that on
    pixel dimensions, and if those are corrected, the character-unit
    dimensions are not recalculated to reflect those corrections.

Below please find a patch that I intend to commit to the emacs-24
branch if no one objects.  Martin, I'd appreciate your review,
especially for the dispnew.c parts.

TIA

--- src/w32term.c~0	2014-05-24 23:48:43 +0300
+++ src/w32term.c	2014-09-21 17:48:00 +0300
@@ -4754,34 +4754,42 @@ w32_read_socket (struct terminal *termin
 	      RECT rect;
 	      int rows, columns, width, height, text_width, text_height;
 
-	      GetClientRect (msg.msg.hwnd, &rect);
-
-	      height = rect.bottom - rect.top;
-	      width = rect.right - rect.left;
-	      text_width = FRAME_PIXEL_TO_TEXT_WIDTH (f, width);
-	      text_height = FRAME_PIXEL_TO_TEXT_HEIGHT (f, height);
-	      rows = FRAME_PIXEL_HEIGHT_TO_TEXT_LINES (f, height);
-	      columns = FRAME_PIXEL_WIDTH_TO_TEXT_COLS (f, width);
-
-	      /* TODO: Clip size to the screen dimensions.  */
-
-	      /* Even if the number of character rows and columns has
-		 not changed, the font size may have changed, so we need
-		 to check the pixel dimensions as well.  */
-
-	      if (width != FRAME_PIXEL_WIDTH (f)
-		  || height != FRAME_PIXEL_HEIGHT (f)
-		  || text_width != FRAME_TEXT_WIDTH (f)
-		  || text_height != FRAME_TEXT_HEIGHT (f))
+	      if (GetClientRect (msg.msg.hwnd, &rect)
+		  /* GetClientRect evidently returns (0, 0, 0, 0) if
+		     called on a minimized frame.  Such "dimensions"
+		     aren't useful anyway.  */
+		  && !(rect.bottom == 0
+		       && rect.top == 0
+		       && rect.left == 0
+		       && rect.right == 0))
 		{
-		  change_frame_size (f, text_width, text_height, 0, 1, 0, 1);
-		  SET_FRAME_GARBAGED (f);
-		  cancel_mouse_face (f);
-		  /* Do we want to set these here ????  */
-/** 		  FRAME_PIXEL_WIDTH (f) = width; **/
-/** 		  FRAME_TEXT_WIDTH (f) = text_width; **/
-/** 		  FRAME_PIXEL_HEIGHT (f) = height; **/
-		  f->win_gravity = NorthWestGravity;
+		  height = rect.bottom - rect.top;
+		  width = rect.right - rect.left;
+		  text_width = FRAME_PIXEL_TO_TEXT_WIDTH (f, width);
+		  text_height = FRAME_PIXEL_TO_TEXT_HEIGHT (f, height);
+		  rows = FRAME_PIXEL_HEIGHT_TO_TEXT_LINES (f, height);
+		  columns = FRAME_PIXEL_WIDTH_TO_TEXT_COLS (f, width);
+
+		  /* TODO: Clip size to the screen dimensions.  */
+
+		  /* Even if the number of character rows and columns
+		     has not changed, the font size may have changed,
+		     so we need to check the pixel dimensions as well.  */
+
+		  if (width != FRAME_PIXEL_WIDTH (f)
+		      || height != FRAME_PIXEL_HEIGHT (f)
+		      || text_width != FRAME_TEXT_WIDTH (f)
+		      || text_height != FRAME_TEXT_HEIGHT (f))
+		    {
+		      change_frame_size (f, text_width, text_height, 0, 1, 0, 1);
+		      SET_FRAME_GARBAGED (f);
+		      cancel_mouse_face (f);
+		      /* Do we want to set these here ????  */
+		      /** 		FRAME_PIXEL_WIDTH (f) = width; **/
+		      /** 		FRAME_TEXT_WIDTH (f) = text_width; **/
+		      /** 		FRAME_PIXEL_HEIGHT (f) = height; **/
+		      f->win_gravity = NorthWestGravity;
+		    }
 		}
 	    }
 


--- src/dispnew.c~1	2014-08-17 07:29:32 +0300
+++ src/dispnew.c	2014-09-22 17:40:15 +0300
@@ -2139,8 +2139,11 @@ adjust_frame_glyphs_for_window_redisplay
 static void
 adjust_decode_mode_spec_buffer (struct frame *f)
 {
+  ssize_t frame_message_buf_size = FRAME_MESSAGE_BUF_SIZE (f);
+
+  eassert (frame_message_buf_size >= 0);
   f->decode_mode_spec_buffer = xrealloc (f->decode_mode_spec_buffer,
-					 FRAME_MESSAGE_BUF_SIZE (f) + 1);
+					 frame_message_buf_size + 1);
 }
 
 
@@ -5540,10 +5543,6 @@ change_frame_size_1 (struct frame *f, in
     {
       new_text_width = (new_width == 0) ? FRAME_TEXT_WIDTH (f) : new_width;
       new_text_height = (new_height == 0) ? FRAME_TEXT_HEIGHT (f) : new_height;
-      /* Consider rounding here: Currently, the root window can be
-	 larger than the frame in terms of columns/lines.  */
-      new_cols = new_text_width / FRAME_COLUMN_WIDTH (f);
-      new_lines = new_text_height / FRAME_LINE_HEIGHT (f);
     }
   else
     {
@@ -5556,6 +5555,12 @@ change_frame_size_1 (struct frame *f, in
   /* Compute width of windows in F.  */
   /* Round up to the smallest acceptable size.  */
   check_frame_size (f, &new_text_width, &new_text_height, 1);
+  /* Recompute the dimensions in character units, since
+     check_frame_size might have changed the pixel dimensions.  */
+  /* Consider rounding here: Currently, the root window can be
+     larger than the frame in terms of columns/lines.  */
+  new_cols = new_text_width / FRAME_COLUMN_WIDTH (f);
+  new_lines = new_text_height / FRAME_LINE_HEIGHT (f);
 
   /* This is the width of the frame without vertical scroll bars and
      fringe columns.  Do this after rounding - see discussion of




In GNU Emacs 24.3.93.1 (i686-pc-mingw32)
 of 2014-08-15 on HOME-C4E4A596F7
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --prefix=/d/usr --enable-checking=yes,glyphs 'CFLAGS=-Og
 -g3''

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x r e o p <backspace> <backspace> p o r t - e m <tab> 
<return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util help-fns mail-prsvr mail-utils time-date tooltip electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp
w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew
greek romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process w32notify w32
multi-tty emacs)

Memory information:
((conses 8 74217 7009)
 (symbols 32 17535 0)
 (miscs 32 33 127)
 (strings 16 10776 4344)
 (string-bytes 1 269654)
 (vectors 8 9550)
 (vector-slots 4 384749 6002)
 (floats 8 57 196)
 (intervals 28 237 95)
 (buffers 508 11))



This bug report was last modified 10 years and 244 days ago.

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