Date: Sat, 13 Sep 1997 13:20:01 -0700 (PDT) From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-bugs Subject: Re: bin/4524 Message-ID: <199709132020.NAA25352@hub.freebsd.org>
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The following reply was made to PR bin/4524; it has been noted by GNATS.
From: j@uriah.heep.sax.de (J Wunsch)
To: freebsd-gnats-submit@freebsd.org
Cc: Subject: Re: bin/4524
Date: Sat, 13 Sep 1997 22:11:28 +0200
(Bounced off by joerg@freebsd.org, so PR # 4526 can be closed as being
a dup for PR # 4524.)
This provides more information for bin/4524
Repeatedly calling realloc causes much more memory to be used
then you'd expect. For example, when procmail tried reading an
8M message, this was sufficient to run a 64M (128M swap) machine
doing nothing else out of swap (and into the ground :-)
This code reproduced the problem outside procmail:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int
main(int argc, char* argv[])
{
size_t size = 0;
char *p = NULL;
int max = 8404992;
if (argc > 2) {
fprintf(stderr, "Usage: %s maxmem\n", argv[0]);
exit(-1);
}
if (argc > 1)
max = atoi(argv[1]);
while(1) {
size += 16384;
if (size > max)
break;
fprintf(stderr, "realloc(%u)\n", size);
if ((p = realloc(p, size)) == NULL) {
fprintf(stderr, "out of memory\n");
exit(-1);
}
}
{
int c;
printf("done. press return to quit\n");
read(0, &c, 1);
}
}
Recompiling the code with the malloc.c from freebsd-current
* $Id: malloc.c,v 1.32 1997/08/31 05:59:39 phk Exp $
fixed things (as did recompiling libc with that malloc.c)
Now the program is killed after getting much further than before;
(I assume when it hits its resource limits) instead of
impacting the machine.
This fix was previously reported by jfieber@indiana.edu back in June
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
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