Description

division by zero in fuction scrolldown at move.c:1739

version

git log
commit ea62cee85e9e77ec86edd9843926dadb69978753 (HEAD -> master, tag: v9.0.1327, origin/master, origin/HEAD)
Author: Bram Moolenaar <Bram@vim.org>
Date:   Sun Feb 19 18:36:41 2023 +0000

    patch 9.0.1327: cursor in wrong position below line with virtual text below

    Problem:    Cursor in wrong position below line with virtual text below ending
                in multi-byte character.
    Solution:   When checking for last character take care of multi-byte
                character.

Proof of Concept

./vim -u NONE -i NONE -n -m -X -Z -e -s -S poc
Floating point exception

DEBUG

gdb --args ./vim -u NONE -i NONE -n -m -X -Z -e -s -S poc
GNU gdb (Ubuntu 12.0.90-0ubuntu1) 12.0.90
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Reading symbols from ./vim...
gdb-peda$ r
Starting program: /home/user/vim/src/vim -u NONE -i NONE -n -m -X -Z -e -s -S poc
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGFPE, Arithmetic exception.
Warning: 'set logging off', an alias for the command 'set logging enabled', is deprecated.
Use 'set logging enabled off'.

Warning: 'set logging on', an alias for the command 'set logging enabled', is deprecated.
Use 'set logging enabled on'.

[----------------------------------registers-----------------------------------]
RAX: 0x8
RBX: 0x7fffffff57c0 --> 0x1
RCX: 0xfffffff8 --> 0x0
RDX: 0x0
RSI: 0x1
RDI: 0x62500001e100 --> 0x3eb
RBP: 0x7fffffff5c00 --> 0x7fffffff5d50 --> 0x7fffffff6010 --> 0x7fffffff62f0 --> 0x7fffffff6c30 --> 0x7fffffff6c60 (--> ...)
RSP: 0x7fffffff5780 --> 0x41b58ab3
RIP: 0x555555c052fa (<scrolldown+7594>:	idiv   DWORD PTR [rbx+0x3dc])
R8 : 0x10007fff68ef --> 0x0
R9 : 0x2
R10: 0xffffffffffffffff
R11: 0x6c ('l')
R12: 0x7fffffffdf78 --> 0x7fffffffe321 ("/home/user/vim/src/vim")
R13: 0x555556219fb0 (<main>:	push   rbp)
R14: 0x55555634bae8 --> 0x5555557e16b0 (<asan.module_dtor>:	push   rbp)
R15: 0x7ffff7ffd040 --> 0x7ffff7ffe2e0 --> 0x555555554000 --> 0x10102464c457f
EFLAGS: 0x10202 (carry parity adjust zero sign trap INTERRUPT direction overflow)
[-------------------------------------code-------------------------------------]
   0x555555c052ed <scrolldown+7581>:	jle    0x555555c0531f <scrolldown+7631>
   0x555555c052f3 <scrolldown+7587>:	mov    eax,DWORD PTR [rbx+0x3c0]
   0x555555c052f9 <scrolldown+7593>:	cdq
=> 0x555555c052fa <scrolldown+7594>:	idiv   DWORD PTR [rbx+0x3dc]
   0x555555c05300 <scrolldown+7600>:	add    eax,DWORD PTR [rbx+0x3bc]
   0x555555c05306 <scrolldown+7606>:	mov    DWORD PTR [rbx+0x3bc],eax
   0x555555c0530c <scrolldown+7612>:	mov    eax,DWORD PTR [rbx+0x3c0]
   0x555555c05312 <scrolldown+7618>:	cdq
[------------------------------------stack-------------------------------------]
0000| 0x7fffffff5780 --> 0x41b58ab3
0008| 0x7fffffff5788 --> 0x55555628b24c ("1 32 8 10 first:1599")
0016| 0x7fffffff5790 --> 0x555555c03550 (<scrolldown>:	push   rbp)
0024| 0x7fffffff5798 --> 0x100000000 --> 0x0
0032| 0x7fffffff57a0 --> 0x62500000a420 --> 0x1
0040| 0x7fffffff57a8 --> 0x0
0048| 0x7fffffff57b0 --> 0x62500000a428 --> 0x0
0056| 0x7fffffff57b8 --> 0x5555561388be (<may_trigger_win_scrolled_resized+2510>:	lea    rsp,[rbp-0x8])
[------------------------------------------------------------------------------]
Legend: code, data, rodata, value
Stopped reason: SIGFPE
0x0000555555c052fa in scrolldown (line_count=0x0, byfold=0x0) at move.c:1739
1739		    row += col / width2;
gdb-peda$ p width2
$1 = 0x0
gdb-peda$ bt
#0  0x0000555555c052fa in scrolldown (line_count=0x0, byfold=0x0) at move.c:1739
#1  0x0000555555c20b33 in check_scrollbind (topline_diff=0x0, leftcol_diff=0x0) at normal.c:1943
#2  0x00005555562238b2 in main_loop (cmdwin=0x1, noexmode=0x0) at main.c:1390
#3  0x0000555555a4c17a in open_cmdwin () at ex_getln.c:4549
#4  0x0000555555a3bfd2 in getcmdline_int (firstc=0x3a, count=0x1, indent=0x0, clear_ccline=0x1) at ex_getln.c:1938
#5  0x0000555555a38809 in getcmdline (firstc=0x3a, count=0x1, indent=0x0, do_concat=GETLINE_CONCAT_CONT) at ex_getln.c:1554
#6  0x0000555555a4101d in getexline (c=0x3a, cookie=0x0, indent=0x0, options=GETLINE_CONCAT_CONT) at ex_getln.c:2843
#7  0x00005555559e2bc3 in do_cmdline (cmdline=0x0, fgetline=0x555555a40f90 <getexline>, cookie=0x0, flags=0x0) at ex_docmd.c:876
#8  0x0000555555c30b82 in nv_colon (cap=0x7fffffff7e60) at normal.c:3176
#9  0x0000555555c1478b in normal_cmd (oap=0x7fffffff8440, toplevel=0x1) at normal.c:938
#10 0x0000555555a14a8d in exec_normal (was_typed=0x0, use_vpeekc=0x0, may_use_terminal_loop=0x0) at ex_docmd.c:8887
#11 0x0000555555a146b4 in exec_normal_cmd (cmd=0x611000000a48 "\\fn0ndwPPPP\\021\\rWPP0rm0<", '0' <repeats 13 times>, remap=0x0, silent=0x0)
    at ex_docmd.c:8850
#12 0x0000555555a14422 in ex_normal (eap=0x7fffffff89a0) at ex_docmd.c:8768
#13 0x00005555559ef8b0 in do_one_cmd (cmdlinep=0x7fffffff9e40, flags=0x7, cstack=0x7fffffff9e60, fgetline=0x555555e0e7b0 <getsourceline>,
    cookie=0x7fffffffae60) at ex_docmd.c:2580
#14 0x00005555559e3675 in do_cmdline (cmdline=0x611000000540 "noaoco\\001\\rr\\027\\027normnorm:", fgetline=0x555555e0e7b0 <getsourceline>,
    cookie=0x7fffffffae60, flags=0x7) at ex_docmd.c:993
#15 0x0000555555e0c5a4 in do_source_ext (fname=0x602000006153 "poc", check_other=0x0, is_vimrc=0x0, ret_sid=0x0, eap=0x0, clearvars=0x0)
    at scriptfile.c:1759
#16 0x0000555555e0a0d1 in do_source (fname=0x602000006153 "poc", check_other=0x0, is_vimrc=0x0, ret_sid=0x0) at scriptfile.c:1905
#17 0x0000555555e09c20 in cmd_source (fname=0x602000006153 "poc", eap=0x7fffffffb820) at scriptfile.c:1250
#18 0x0000555555e0971e in ex_source (eap=0x7fffffffb820) at scriptfile.c:1276
#19 0x00005555559ef8b0 in do_one_cmd (cmdlinep=0x7fffffffccc0, flags=0xb, cstack=0x7fffffffcce0, fgetline=0x0, cookie=0x0) at ex_docmd.c:2580
#20 0x00005555559e3675 in do_cmdline (cmdline=0x602000002710 "so poc", fgetline=0x0, cookie=0x0, flags=0xb) at ex_docmd.c:993
#21 0x00005555559e6771 in do_cmdline_cmd (cmd=0x602000002710 "so poc") at ex_docmd.c:587
#22 0x0000555556222b5d in exe_commands (parmp=0x555556e0ac00 <params>) at main.c:3146
#23 0x000055555622095b in vim_main2 () at main.c:782
#24 0x000055555621a56f in main (argc=0xd, argv=0x7fffffffdf78) at main.c:433
#25 0x00007ffff7c45d90 in __libc_start_call_main (main=main@entry=0x555556219fb0 <main>, argc=argc@entry=0xd, argv=argv@entry=0x7fffffffdf78)
    at ../sysdeps/nptl/libc_start_call_main.h:58
#26 0x00007ffff7c45e40 in __libc_start_main_impl (main=0x555556219fb0 <main>, argc=0xd, argv=0x7fffffffdf78, init=<optimized out>, fini=<optimized out>,
    rtld_fini=<optimized out>, stack_end=0x7fffffffdf68) at ../csu/libc-start.c:392
#27 0x0000555555721a75 in _start ()
gdb-peda$ list
1734		    col -= width1;
1735		    ++row;
1736		}
1737		if (col > width2)
1738		{
1739		    row += col / width2;
1740		    col = col % width2;
1741		}
1742		if (row >= curwin->w_height)
1743		{

poc