From: sretzki@gmx.de
To: 9fans@cse.psu.edu
Subject: [9fans] memory woes
Date: Fri, 5 Jan 2007 15:36:32 +0100 [thread overview]
Message-ID: <329de470156ae34054ae5f9314a37c49@mail.gmx.net> (raw)
Hi all,
I got this code:
#include <u.h>
#include <libc.h>
void main(int argc, char **argv) {
int i;
char *m00;
for(i=0; i<=5; i++) {
if((m00 = malloc(strlen("Hello World"))) == nil) {
print("drama! [%d]\n",i);
exits("malloc");
}
strcpy(m00,"Hello World");
print("%d> %s\n",i,m00);
free(m00);
}
exits(nil);
}
If I run that, I get:
term% 8c foo.c && 8l foo.8
term% 8.out
0> Hello World
mem user overflow
pool sbrkmem block a460
hdr 0a110c09 00000040 0000104f 00000000 6c6c6548 6f57206f
tail 00000000 00000000 00000000 00000000 00000000 00000000 | ef2d00be 00000040
user data 6c 6f 20 57 6f 72 6c 64 | 00 fe f1 f0 00 00 00 00
panic: pool panic
8.out 1430: suicide: sys: trap: fault read addr=0x0 pc=0x0000324a
term%
Without the free()-call in the loop, it does not crash - why is that? Also, I see programs just get killed without any warning/error-message anywhere - commenting out random free() calls seem to help ^^
Can somebody explain what is going on?
Mfg, Sascha
next reply other threads:[~2007-01-05 14:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-05 14:36 sretzki [this message]
2007-01-05 14:44 ` erik quanstrom
2007-01-05 14:51 ` sretzki
2007-01-05 14:53 ` Axel Belinfante
2007-01-05 14:54 erik quanstrom
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=329de470156ae34054ae5f9314a37c49@mail.gmx.net \
--to=sretzki@gmx.de \
--cc=9fans@cse.psu.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).