Date: Mon, 7 Jun 2004 16:38:21 -0400 (EDT) From: Robert Watson <rwatson@freebsd.org> To: Arjan van Leeuwen <avleeuwen@piwebs.com> Cc: "David A. Benfell" <benfell@parts-unknown.org> Subject: Re: file descripter leak in current with Qmail? Message-ID: <Pine.NEB.3.96L.1040607163727.88690H-200000@fledge.watson.org> In-Reply-To: <200406072216.29044.avleeuwen@piwebs.com>
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[-- Attachment #1 --]
On Mon, 7 Jun 2004, Arjan van Leeuwen wrote:
> On Monday 07 June 2004 21:42, you wrote:
> > On Mon, 7 Jun 2004, Arjan van Leeuwen wrote:
> > > > > In terms of debugging it: your first task it to identify if there's
> > > > > one process that's holding all the fd's, or if it is distributed over
> > > > > many proceses. After that, you want to track down what kind of fd is
> > > > > being left open, which may help you track down why it's left open...
> > > >
> > > > Just as I'm reading this, I'm seeing the same thing on my -CURRENT
> > > > server, which has a _very_ low load (atm, it's only routing the
> > > > internet traffic for 3 users and serving SMTP for 2 of them). I'm also
> > > > running qmail. The kernel is from June 6. How do I go about
> > > > investigating this further?
> > >
> > > Replying to myself -
> > > fstat shows all open files evenly distributed among the running
> > > processes.
> >
> > It could be that this is related to the esd file descriptor leak problem
> > also being reported. You might also try the attached patch.
>
> I get a panic (address not allocated) when using the patch. I can't
> write down any useful details about it right now, because although the
> server has only 3 users, they're very disconcerned when I disrupt their
> internet traffic :).
Doh. Sorry about that. Revised patch attached. I'm able to test the
leak with the attached C file, and on my test box (now that it doesn't
panic), the leak appears fixed for non-blocking accepts.
Robert N M Watson FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org Senior Research Scientist, McAfee Research
Index: uipc_syscalls.c
===================================================================
RCS file: /data/ncvs/src/sys/kern/uipc_syscalls.c,v
retrieving revision 1.187
diff -u -r1.187 uipc_syscalls.c
--- uipc_syscalls.c 7 Jun 2004 09:59:50 -0000 1.187
+++ uipc_syscalls.c 7 Jun 2004 20:21:30 -0000
@@ -253,7 +253,7 @@
{
struct filedesc *fdp;
struct file *nfp = NULL;
- struct sockaddr *sa;
+ struct sockaddr *sa = NULL;
socklen_t namelen;
int error;
struct socket *head, *so;
@@ -285,7 +285,7 @@
if ((head->so_state & SS_NBIO) && TAILQ_EMPTY(&head->so_comp)) {
ACCEPT_UNLOCK();
error = EWOULDBLOCK;
- goto done;
+ goto noconnection;
}
while (TAILQ_EMPTY(&head->so_comp) && head->so_error == 0) {
if (head->so_state & SS_CANTRCVMORE) {
@@ -296,14 +296,14 @@
"accept", 0);
if (error) {
ACCEPT_UNLOCK();
- goto done;
+ goto noconnection;
}
}
if (head->so_error) {
error = head->so_error;
head->so_error = 0;
ACCEPT_UNLOCK();
- goto done;
+ goto noconnection;
}
so = TAILQ_FIRST(&head->so_comp);
KASSERT(!(so->so_qstate & SQ_INCOMP), ("accept1: so SQ_INCOMP"));
[-- Attachment #2 --]
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main(int argc, char *argv[])
{
struct sockaddr_in sin;
socklen_t size;
int i, s;
s = socket(PF_INET, SOCK_STREAM, 0);
if (s == -1) {
perror("socket");
exit(-1);
}
bzero(&sin, sizeof(sin));
sin.sin_len = sizeof(sin);
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = htons(8080);
if (bind(s, (struct sockaddr *) &sin, sizeof(sin)) != 0) {
perror("bind");
exit(-1);
}
if (listen(s, -1) != 0) {
perror("listen");
exit(-1);
}
i = 1;
if (fcntl(s, O_NONBLOCK, &i) != 0) {
perror("O_NONBLOCK");
exit(-1);
}
for (i = 0; i < 1000; i++)
accept(s, (struct sockaddr *)&sin, &size);
printf("fd returned by open(/dev/null) = %d\n",
open("/dev/null", O_RDONLY));
return (0);
}
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