Date: Thu, 7 Dec 2000 14:34:11 -0800 (PST) From: chrisp@netwinsite.com To: freebsd-gnats-submit@FreeBSD.org Subject: misc/23364: gethostbyaddr takes longer or locks up and burns cpu when linked to -pthread Message-ID: <200012072234.eB7MYBv07910@freefall.freebsd.org> Resent-Message-ID: <200012072240.eB7Me1F08592@freefall.freebsd.org>
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>Number: 23364
>Category: misc
>Synopsis: gethostbyaddr takes longer or locks up and burns cpu when linked to -pthread
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Dec 07 14:40:01 PST 2000
>Closed-Date:
>Last-Modified:
>Originator: Chris Pugmire
>Release: 4.1.1-RELEASE
>Organization:
NetWin Ltd
>Environment:
FreeBSD news.siscom.net 4.1.1-RELEASE FreeBSD 4.1.1-RELEASE #2: Mon Nov 27 14:21:06 EST 2000 root@news.siscom.net:/usr/src/sys/compile/GENERIC i386
>Description:
With a test program doing ip number to name lookups for a number that
does not have an entry if the program is linked with -pthread then
it takes 30 seconds longer and burns 100% cpu until it times out.
I believe it sometimes never times out or takes much longer but cannot
reproduce this in a test case.
Note that no actual threads are used, this program is simply linked
with -pthread and then behaves in this odd way.
>How-To-Repeat:
Sample code included:
(include headers...)
int do_reverse(char *ipnum);
int main(int argc, char *argv[])
{
int i;
if (argc<2) {
usage: printf("Usage: testdns -rev n.n.n.n\n");
return 0;
}
tcp_startup();
for (i=1; i<argc; i++) {
if (strncmp(argv[i],"-rev",4)==0) {
do_reverse(argv[++i]);
} else {
printf("Invalid option (%s)\n",argv[i]);
goto usage;
}
}
return 0;
}
int do_reverse(char *ipnum)
{
struct sockaddr_in sin;
struct hostent *hp;
int start;
start = time(NULL);
sin.sin_addr.s_addr = inet_addr(ipnum);
printf("Looking up (%s)\n",ipnum);
hp = gethostbyaddr( (char *) &(sin.sin_addr), sizeof(sin.sin_addr), AF_INET);
printf("Result %p\n",hp);
if (hp!=NULL) if (hp->h_name!=NULL) {
printf("result (%s)\n",hp->h_name);
}
printf("Delay %d seconds\n",time(NULL)-start);
return TRUE;
}
Example output with the same program linked different ways:
news# ./testdns_nopthread -rev 160.79.54.12
Looking up (160.79.54.12)
Result 0x0
Delay 80 seconds
news# ./testdns_pthread -rev 160.79.54.12
Looking up (160.79.54.12)
Result 0x0
Delay 111 seconds
(and in the second case watching top will show the testdns process
burning cpu)
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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