Re: zsh eats 100% CPU with completion in /

[Mikael Magnusson <mikachu@gmail.com>]

2009/10/30 Mikael Magnusson <mikachu@gmail.com>:
> 2009/10/30 Frank Terbeck <ft@bewatermyfriend.org>:
>> The subject is not entirely correct.
>>
>> Zsh eats 100% CPU on a colleague's laptop if you do this:
>> % cd /
>> % cd ..
>> % ./<tab>
>>
>> Happens with the most recent CVS HEAD, too.
>> That's on linux (debian stable, actually).
>>
>> The problem is reproducible on his machine. And it doesn't happen if
>> you do this:
>> % cd /
>> % ./<tab>
>>
>> The 'cd ..' is required.
>>
>> I cannot reproduce the problem on my system with exactly the same
>> configuration and with exactly the same zsh version. And I am in fact
>> using the very same OS (debian stable), too.
>>
>> As you can imagine, I am quite puzzled and I don't know how to tackle
>> this.
>>
>> Any hints or suggestions are highly welcome.
>
> I can reproduce this, but not under gdb, and, curiously, not if I
> first start another instance of zsh, ie:
> %(1) zsh
> %(2) cd /
> %(2) cd ..
> %(2) <tab> -> produces listing
> %(2) exit
> %(1) cd /
> %(1) cd ..
> %(1) <tab> -> hangs
>
> Here's a backtrace without debug symbols while i rebuild:

And here's a real one, and stepping until it seems to repeat. The /*
Probably shouldn't happen */ comment looks particularly suspicious.

(gdb) bt
#0  mb_metacharinit () at utils.c:448
#1  0x080d378c in itype_end (ptr=0x830a100 "", itype=128, once=1) at
utils.c:3310
#2  0x6fa39a38 in get_comp_string () at zle_tricky.c:1450
#3  0x6fa372bc in docomplete (lst=4) at zle_tricky.c:659
#4  0x6fa3675f in expandorcomplete (args=0x6fa4cd40) at zle_tricky.c:315
#5  0x6fa36302 in completecall (args=0x6fa4cd40) at zle_tricky.c:208
#6  0x6fa25fcd in execzlefunc () from /usr/local/lib/zsh/4.3.10-dev-1/zsh/zle.so
#7  0x6fa261f2 in zlecore () from /usr/local/lib/zsh/4.3.10-dev-1/zsh/zle.so
#8  0x6fa267f9 in zleread () from /usr/local/lib/zsh/4.3.10-dev-1/zsh/zle.so
#9  0x6fa28867 in zle_main_entry () from
/usr/local/lib/zsh/4.3.10-dev-1/zsh/zle.so
#10 0x08086cda in zleentry (cmd=1) at init.c:1304
#11 0x08087b93 in inputline ()
#12 0x08087dc8 in ingetc ()
#13 0x0807d595 in ihgetc () at hist.c:263
#14 0x08091c26 in zshlex ()
#15 0x080ab108 in parse_event () at parse.c:451
#16 0x08084209 in loop (toplevel=1, justonce=0) at init.c:132
#17 0x08087053 in zsh_main (argc=1, argv=0x77c043c4) at init.c:1454
#18 0x08055522 in main ()
(gdb) s
449	}
(gdb)
itype_end (ptr=0x830a100 "", itype=128, once=1) at utils.c:3311
3311		while (*ptr) {
(gdb)
3376	    return (char *)ptr;
(gdb)
3377	}
(gdb)
get_comp_string () at zle_tricky.c:1451
1451			    nnb = tt + nclen;
(gdb)
1452			tt += nclen;
(gdb)
1439		for (tt = s; tt < s + zlemetacs_qsub - wb;) {
(gdb)
1440		    if (*tt == Inbrack) {
(gdb)
1445		    } else if (i && *tt == Outbrack) {
(gdb)
1449			int nclen = MB_METACHARLEN(tt);
(gdb)
mb_metacharlenconv (s=0x830a100 "", wcp=0x0) at utils.c:4254
4254	    if (!isset(MULTIBYTE)) {
(gdb)
4270	    if (itok(*s)) {
(gdb)
4276	    return mb_metacharlenconv_r(s, wcp, &mb_shiftstate);
(gdb)
mb_metacharlenconv_r (s=0x830a100 "", wcp=0x0, mbsp=0x80f0ccc) at utils.c:4205
4205	    size_t ret = MB_INVALID;
(gdb)
4210	    for (ptr = s; *ptr; ) {
(gdb)
4229	    if (wcp)
(gdb)
4232	    memset(mbsp, 0, sizeof(*mbsp));
(gdb)
4233	    if (ptr > s) {
(gdb)
4236		return 0;		/* Probably shouldn't happen */
(gdb)
4237	}
(gdb)
mb_metacharlenconv (s=0x830a100 "", wcp=0x0) at utils.c:4277
4277	}
(gdb)
get_comp_string () at zle_tricky.c:1450
1450			if (itype_end(tt, IIDENT, 1) == tt)
(gdb)
itype_end (ptr=0x830a100 "", itype=128, once=1) at utils.c:3308
3308	    if (isset(MULTIBYTE) &&
(gdb)
3310		mb_metacharinit();
(gdb)
mb_metacharinit () at utils.c:448
448	    memset(&mb_shiftstate, 0, sizeof(mb_shiftstate));
(gdb)
449	}
(gdb)
itype_end (ptr=0x830a100 "", itype=128, once=1) at utils.c:3311
3311		while (*ptr) {


-- 
Mikael Magnusson