Re: [Patch] ipvs: close race conditions on ip_vs_conn_tab list modification

On Fri, Jun 24, 2005 at 06:09:40PM +0300, Julian Anastasov wrote:

quoted

	Hello,

On Fri, 24 Jun 2005, Neil Horman wrote:

quoted

 			if (ct) {
 				IP_VS_DBG(4, "del conn template\n");
 				ip_vs_conn_expire_now(ct);
 			}

	Don't forget to use cp->control instead of ct, ct is not needed
anymore.

Regards

--
Julian Anastasov [off-list ref]

Good catch.  Sorry, should have seen that earlier.  New patch attached with
corrections.  When you're comfortable with this, I'll post the 2.4 version of
the patch.

Regards
Neil

Signed-off-by: Neil Horman <redacted>

ip_vs_conn.c |   24 ++++--------------------
1 files changed, 4 insertions(+), 20 deletions(-)

--- linux-2.6.git/net/ipv4/ipvs/ip_vs_conn.c.orig	2005-06-23 13:11:00.000000000 -0400
+++ linux-2.6.git/net/ipv4/ipvs/ip_vs_conn.c	2005-06-24 13:33:03.000000000 -0400

@@ -548,7 +548,6 @@

{
	if (del_timer(&cp->timer))
		mod_timer(&cp->timer, jiffies);
-	__ip_vs_conn_put(cp);
}

@@ -801,21 +800,12 @@

					continue;
			}

-			/*
-			 * Drop the entry, and drop its ct if not referenced
-			 */
-			atomic_inc(&cp->refcnt);
-			ct_write_unlock(hash);
-
-			if ((ct = cp->control))
-				atomic_inc(&ct->refcnt);
			IP_VS_DBG(4, "del connection\n");
			ip_vs_conn_expire_now(cp);
-			if (ct) {
+			if (cp->control) {
				IP_VS_DBG(4, "del conn template\n");
-				ip_vs_conn_expire_now(ct);
+				ip_vs_conn_expire_now(cp->control);
			}
-			ct_write_lock(hash);
		}
		ct_write_unlock(hash);
	}

@@ -829,7 +819,6 @@

{
	int idx;
	struct ip_vs_conn *cp;
-	struct ip_vs_conn *ct;

  flush_again:
	for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {

@@ -839,18 +828,13 @@

		ct_write_lock_bh(idx);

		list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
-			atomic_inc(&cp->refcnt);
-			ct_write_unlock(idx);

-			if ((ct = cp->control))
-				atomic_inc(&ct->refcnt);
			IP_VS_DBG(4, "del connection\n");
			ip_vs_conn_expire_now(cp);
-			if (ct) {
+			if (cp->control) {
				IP_VS_DBG(4, "del conn template\n");
-				ip_vs_conn_expire_now(ct);
+				ip_vs_conn_expire_now(cp->control);
			}
-			ct_write_lock(idx);
		}
		ct_write_unlock_bh(idx);
	}
-- 
/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
*nhorman@redhat.com
*gpg keyid: 1024D / 0x92A74FA1
*http://pgp.mit.edu
***************************************************/