Bug 3129 - Memory leak in GLIBC 2.1 in gethostbyaddr
Memory leak in GLIBC 2.1 in gethostbyaddr
Status: CLOSED DUPLICATE of bug 3560
Product: Red Hat Linux
Classification: Retired
Component: glibc (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Cristian Gafton
Depends On:
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Reported: 1999-05-28 14:53 EDT by grumple
Modified: 2008-05-01 11:37 EDT (History)
1 user (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 1999-07-02 16:42:20 EDT
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Description grumple 1999-05-28 14:53:51 EDT
After installing Redhat 6.0 on a production server, I
noticed a problem with syslogd.  syslogd was growing in
memory size proportional to the amount of data received.
This is a box that is doing lots and lots of syslogging from
lots of hosts.

Well after some investigation, and examining of the source
code, I have isolated the bug.  And I am including a sample
program that shows the bug.

It appears that if you call gethostbyaddr, and if the
address is not in /etc/hosts, the gethostbyaddr call leaks
memory.  If the address is in /etc/hosts (which is what we
did to solve the problem for now), it does not leak.  The
program below will call gethostbyaddr 100,000 times, and
then pause so you can take a look at the size of the
process.  Under 5.2 the process does not grow in size.
Under 6.0 the process grows rapidly.

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
void main()
        unsigned long n = 0x24b445cf;
        int i;
        struct hostent *hp = 0, *ohp = 0;
        struct sockaddr_in f;
        struct sockaddr_in *f2 = &f;
        f.sin_addr.s_addr = 0xCF45B424;
        f.sin_family = AF_INET;
        for (i=0; i<100000; i++) {
                hp = gethostbyaddr((char *) &n, 4, 2);
                if (ohp != hp)
                    printf("HP CHANGED (%d != %d)\n", ohp,
                ohp = hp;
                if (!(i % 1000))
        printf("Press <RETURN>... ");
Comment 1 Cristian Gafton 1999-07-02 16:42:59 EDT
*** This bug has been marked as a duplicate of 3560 ***

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