On Thu, Dec 09, 2004 at 10:40:40PM +0100, Glynn Clements via RT wrote:
guest user via RT wrote:
> Trying to fix the new (at least recently discovered) bug
> in r.stats:
>
> lib/gis/cats.c
>
> int
> G_set_raster_cats_title (char *title, struct Categories *pcats)
> {
> if (title == NULL) title="";
> pcats->title = G_store (title); <- it crashes here
> G_newlines_to_spaces (pcats->title);
> G_strip (pcats->title);
> return 0;
> }
>
> For the crashing map title="" (so above if condition used).
> Reverting locally store.c (G_store() function) didn't help.G_store() calls G_malloc() which calls malloc().
If a program crashes in either malloc (or calloc, realloc etc) or
free, it's usually because the heap has become corrupted, typically
because something wrote beyond the bounds of a dynamically-allocated
block, overwriting the header of either the current block or the one
after it.IOW, the crash is just a symptom; the bug lies elsewhere.
First question:
Is nobody able to reproduce this bug in GRASS 5.7/Spearfish 5.7:
r.stats -anC fields,elevation.10m
If no, maybe my gcc version is corrupted?
gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-42)
?
Locating this kind of bug can be awkward, as there tend not to be any
detectable side-effects at the point when the memory is corrupted.There are various tools which can be used, including the MALLOC_CHECK_
environment variable and mcheck/mprobe functions (see the libc Info
file for details), and third-party memory debugging libraries such as
Electric Fence.
Unfortunately I have not slightest idea of the suggested tools.
Markus