bug#13717: scrolling very fast makes emacs-nox segfault

bug#13717: scrolling very fast makes emacs-nox segfault

[Troy Sankey]

Steps:
1. install GNU Emacs 24.2 (openSUSE 12.2)
2. delete ~/.emacs
3. open gnome-terminal (I'm using gnome-shell)
4. $ emacs-nox
5. scroll very fast -- I've tried both mouse wheel and touchpad
6. segfault

I can't get a proper backtrace because I don't have the appropriate
debugging symbols. I've installed emacs-debuginfo and
emacs-nox-debuginfo, but that did not help.

Troy

bug#13717: scrolling very fast makes emacs-nox segfault

[Eli Zaretskii]

> From: Troy Sankey <sankeytms@gmail.com>
> Date: Thu, 14 Feb 2013 19:42:09 -0800
> 
> Steps:
> 1. install GNU Emacs 24.2 (openSUSE 12.2)
> 2. delete ~/.emacs
> 3. open gnome-terminal (I'm using gnome-shell)
> 4. $ emacs-nox
> 5. scroll very fast -- I've tried both mouse wheel and touchpad
> 6. segfault

Scroll which file?  The *scratch* buffer is too short, and cannot be
scrolled.

> I can't get a proper backtrace because I don't have the appropriate
> debugging symbols. I've installed emacs-debuginfo and
> emacs-nox-debuginfo, but that did not help.

I hope someone can post a backtrace, because this is 100% not
reproducible on my system (but I don't have gnome-terminal or
gnome-shell).

Also, could you perhaps try a recent pretest of Emacs 24.3?  If that
problem doesn't exist there, it probably was already solved.

bug#13717: scrolling very fast makes emacs-nox segfault

[Glenn Morris]

Eli Zaretskii wrote:

> I hope someone can post a backtrace, because this is 100% not
> reproducible on my system (but I don't have gnome-terminal or
> gnome-shell).

Nor on mine (I did try gnome-terminal inside gnome-shell, and scrolled
24.2 as fast as I could).

bug#13717: scrolling very fast makes emacs-nox segfault

[Troy Sankey]

[-- Attachment #1: Type: text/plain, Size: 898 bytes --]

> Scroll which file?  The *scratch* buffer is too short, and cannot be
> scrolled.

Yes, the *scratch* buffer (but any buffer will do). It doesn't visually
scroll, but on my machine scrolling produces a lot of audible bells and
emacs keeps saying "Beginning/End of buffer".

> I hope someone can post a backtrace, because this is 100% not
> reproducible on my system (but I don't have gnome-terminal or
> gnome-shell).

I was able to produce a backtrace by ensuring my *-debuginfo packages
were the same version as my emacs packages :P  I'm not entirely sure how
this bug tracker takes pastes... so I've attached it. Also mirrored
here: http://eserver.sytes.net/tmp/emacs-nox-scrolling-bt.txt

> Also, could you perhaps try a recent pretest of Emacs 24.3?  If that
> problem doesn't exist there, it probably was already solved.

I'm a little busy, but I'll get back to compiling emacs later today.

[-- Attachment #2: emacs-nox-scrolling-bt.txt --]
[-- Type: text/plain, Size: 1643 bytes --]

#0  0x00000000004ed5a3 in lisp_align_malloc (type=type@entry=MEM_TYPE_CONS, nbytes=1008) at alloc.c:1118
#1  0x00000000004ed966 in Fcons (car=11457778, cdr=<optimized out>) at alloc.c:2775
#2  0x00000000004a5ec0 in Fkey_binding (key=key@entry=11461349, accept_default=11407954, no_remap=11408002, position=11407954) at keymap.c:1714
#3  0x00000000004a6085 in Fcommand_remapping (keymaps=<optimized out>, position=<optimized out>, command=<optimized out>) at keymap.c:1249
#4  Fcommand_remapping (command=<optimized out>, position=<optimized out>, keymaps=<optimized out>) at keymap.c:1240
#5  0x000000000049e5d3 in read_key_sequence (keybuf=keybuf@entry=0x7fffffffd330, prompt=11407954, dont_downcase_last=dont_downcase_last@entry=0, can_return_switch_frame=can_return_switch_frame@entry=1, fix_current_buffer=fix_current_buffer@entry=1, bufsize=30) at keyboard.c:10055
#6  0x000000000049edfc in command_loop_1 () at keyboard.c:1449
#7  0x00000000005053d1 in internal_condition_case (bfun=bfun@entry=0x49ec10 <command_loop_1>, handlers=11475938, hfun=hfun@entry=0x494a10 <cmd_error>) at eval.c:1514
#8  0x000000000049351e in command_loop_2 (ignore=ignore@entry=11407954) at keyboard.c:1160
#9  0x00000000005052cb in internal_catch (tag=<error reading variable: Cannot access memory at address 0xffffffffffffffe2>, func=func@entry=0x493500 <command_loop_2>, arg=11407954) at eval.c:1271
#10 0x00000000004944f7 in command_loop () at keyboard.c:1139
#11 recursive_edit_1 () at keyboard.c:759
#12 0x0000000000494825 in Frecursive_edit () at keyboard.c:823
#13 0x0000000000407e5d in main (argc=<optimized out>, argv=0x7fffffffdb58) at emacs.c:1715

bug#13717: scrolling very fast makes emacs-nox segfault

[Troy Sankey]

> I'm a little busy, but I'll get back to compiling emacs later today.

I compiled trunk, and it does not segfault no matter how fast I scroll.

I used the following flags:

 --with-gpm \
 --without-x \
 --without-sound \
 --without-sync-input \
 --without-xpm \
 --without-jpeg \
 --without-tiff \
 --without-gif \
 --without-png

which are the same flags used in the emacs RPM for openSUSE.

bug#13717: scrolling very fast makes emacs-nox segfault

[Glenn Morris]

Troy Sankey wrote:

>> I'm a little busy, but I'll get back to compiling emacs later today.
>
> I compiled trunk, and it does not segfault no matter how fast I scroll.

Could you also try

http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.93.tar.xz

bug#13717: scrolling very fast makes emacs-nox segfault

[Troy Sankey]

Glenn Morris wrote:

> Could you also try
> 
> http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.93.tar.xz

Here are the results of my compile-spree:
http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.93.tar.xz -> works
http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.90.tar.gz -> works
ftp://ftp.gnu.org/gnu/emacs/emacs-24.2.tar.xz ---------------> crashes

bug#13717: scrolling very fast makes emacs-nox segfault

[Glenn Morris]

Version: 24.3

Troy Sankey wrote:

> Here are the results of my compile-spree:
> http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.93.tar.xz -> works
> http://alpha.gnu.org/gnu/emacs/pretest/emacs-24.2.90.tar.gz -> works
> ftp://ftp.gnu.org/gnu/emacs/emacs-24.2.tar.xz ---------------> crashes

Great, thanks.
This means it (whatever it is) will be fixed in the upcoming Emacs 24.3
release.