Re: zsh eats 100% CPU with completion in /

[Mikael Magnusson <mikachu@gmail.com>]

2009/11/2 Mikael Magnusson <mikachu@gmail.com>:

> Here we are,
>
> (gdb) watch lextok2['/']
> Hardware watchpoint 9: lextok2['/']
> Continuing.
> Hardware watchpoint 9: lextok2['/']
>
> Old value = 47 '/'
> New value = 0 '\000'
> 0x080c962f in xsymlinks (s=0x818e8f1 "..") at utils.c:696
> 696                 *p = '\0';
>
> (start over and add breakpoints (i'm not in reversible now just to be safe))
>
> 692                 if (!strcmp(xbuf, "/"))
> (gdb) print xbuf
> $22 = '\000' <repeats 8191 times>
> (gdb) n
> 694                 p = xbuf + strlen(xbuf);
> (gdb)
> 695                 while (*--p != '/');
> (gdb) n
> at this point i pressed ctrl-c because i was curious what was taking
> so long. Apparently this loops over all memory until it finds a slash,
> which takes a while under gdb. Also apparently, the first / it finds
> is in lextok2.

And this seems to fix it. Not sure if checking that inside the loop is the best
place, but there seems to be some freeing of *pp going on that I
didn't feel like
investigating. Maybe checking xbuf before slashsplit would work?

diff --git a/Src/utils.c b/Src/utils.c
index 2a05624..634edc5 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -691,6 +691,8 @@ xsymlinks(char *s)
 	    zsfree(*pp);
 	    if (!strcmp(xbuf, "/"))
 		continue;
+	    if (!*xbuf)
+		continue;
 	    p = xbuf + strlen(xbuf);
 	    while (*--p != '/');
 	    *p = '\0';

-- 
Mikael Magnusson