[Ocfs2-devel] [patch 03/11] ocfs2/o2net: incorrect to terminate accepting connections loop upon rejecting an invalid one
Andrew Morton
akpm at linux-foundation.org
Wed Mar 19 14:01:43 PDT 2014
On Fri, 24 Jan 2014 14:22:57 -0800 tariq saeed <tariq.x.saeed at oracle.com> wrote:
> On 1/24/2014 1:55 PM, Mark Fasheh wrote:
> > On Fri, Jan 24, 2014 at 12:47:02PM -0800, akpm at linux-foundation.org wrote:
> >> From: Tariq Saeed <tariq.x.saeed at oracle.com>
> >> Subject: ocfs2/o2net: incorrect to terminate accepting connections loop upon rejecting an invalid one
> >>
> >> When o2net-accept-one() rejects an illegal connection, it terminates the
> >> loop picking up the remaining queued connections. This fix will continue
> >> accepting connections till the queue is emtpy.
> >>
> >> Addresses Orabug 17489469.
> > Thanks for sending this, review comments below.
> >
> >
> >> diff -puN fs/ocfs2/cluster/tcp.c~ocfs2-o2net-incorrect-to-terminate-accepting-connections-loop-upon-rejecting-an-invalid-one fs/ocfs2/cluster/tcp.c
> >> --- a/fs/ocfs2/cluster/tcp.c~ocfs2-o2net-incorrect-to-terminate-accepting-connections-loop-upon-rejecting-an-invalid-one
> >> +++ a/fs/ocfs2/cluster/tcp.c
> >> @@ -1826,7 +1826,7 @@ int o2net_register_hb_callbacks(void)
> >>
> >> /* ------------------------------------------------------------ */
> >>
> >> -static int o2net_accept_one(struct socket *sock)
> >> +static int o2net_accept_one(struct socket *sock, int *more)
> >> {
> >> int ret, slen;
> >> struct sockaddr_in sin;
> >> @@ -1837,6 +1837,7 @@ static int o2net_accept_one(struct socke
> >> struct o2net_node *nn;
> >>
> >> BUG_ON(sock == NULL);
> >> + *more = 0;
> >> ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
> >> sock->sk->sk_protocol, &new_sock);
> >> if (ret)
> >> @@ -1848,6 +1849,7 @@ static int o2net_accept_one(struct socke
> >> if (ret < 0)
> >> goto out;
> >>
> >> + *more = 1;
> >> new_sock->sk->sk_allocation = GFP_ATOMIC;
> >>
> >> ret = o2net_set_nodelay(new_sock);
> >> @@ -1949,8 +1951,15 @@ out:
> >> static void o2net_accept_many(struct work_struct *work)
> >> {
> >> struct socket *sock = o2net_listen_sock;
> >> - while (o2net_accept_one(sock) == 0)
> >> + int more;
> >> + int err;
> >> +
> >> + for (;;) {
> >> + err = o2net_accept_one(sock, &more);
> >> + if (!more)
> >> + break;
> > We're throwing out 'err' here and trusting the variable 'more'. However, err
> > could be set and more would be 0 regardless of whether there actually are
> > more connections to be had. This makes more sense given when 'more' is set:
>
> Thanks for the comments.
> To understand the consequences of ignoring the err, we need to look at
> what is going on.
> We get a softIRQ when a connection packet (tcp SYN). It is critical to
> note that we may not
> get a softIRQ_for every connection s_ince connection packets can arrive
> back-to-back (as happened in this bug). So, one softIRQ could be
> delivered for > 1 pending accept.
> _This is the KEY point. _
>
> If we terminate the loop calling o2net_accept_one() upon seeing an
> error, what happens
> to the rest of the connections in the queue. If no new connection
> arrives for hours, no new softIRQ
> will be delivered, and the connections will just sit in the queue.
Please note that I had to edit your email to undo the top-posting so I
could reply to it. Please don't top-post.
Mark, are you now OK with the patch as-is?
From: Tariq Saeed <tariq.x.saeed at oracle.com>
Subject: ocfs2/o2net: incorrect to terminate accepting connections loop upon rejecting an invalid one
When o2net-accept-one() rejects an illegal connection, it terminates the
loop picking up the remaining queued connections. This fix will continue
accepting connections till the queue is emtpy.
Addresses Orabug 17489469.
Signed-off-by: Tariq Saseed <tariq.x.saeed at oracle.com>
Cc: Mark Fasheh <mfasheh at suse.com>
Cc: Joel Becker <jlbec at evilplan.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
fs/ocfs2/cluster/tcp.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff -puN fs/ocfs2/cluster/tcp.c~ocfs2-o2net-incorrect-to-terminate-accepting-connections-loop-upon-rejecting-an-invalid-one fs/ocfs2/cluster/tcp.c
--- a/fs/ocfs2/cluster/tcp.c~ocfs2-o2net-incorrect-to-terminate-accepting-connections-loop-upon-rejecting-an-invalid-one
+++ a/fs/ocfs2/cluster/tcp.c
@@ -1826,7 +1826,7 @@ int o2net_register_hb_callbacks(void)
/* ------------------------------------------------------------ */
-static int o2net_accept_one(struct socket *sock)
+static int o2net_accept_one(struct socket *sock, int *more)
{
int ret, slen;
struct sockaddr_in sin;
@@ -1837,6 +1837,7 @@ static int o2net_accept_one(struct socke
struct o2net_node *nn;
BUG_ON(sock == NULL);
+ *more = 0;
ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
sock->sk->sk_protocol, &new_sock);
if (ret)
@@ -1848,6 +1849,7 @@ static int o2net_accept_one(struct socke
if (ret < 0)
goto out;
+ *more = 1;
new_sock->sk->sk_allocation = GFP_ATOMIC;
ret = o2net_set_nodelay(new_sock);
@@ -1949,8 +1951,15 @@ out:
static void o2net_accept_many(struct work_struct *work)
{
struct socket *sock = o2net_listen_sock;
- while (o2net_accept_one(sock) == 0)
+ int more;
+ int err;
+
+ for (;;) {
+ err = o2net_accept_one(sock, &more);
+ if (!more)
+ break;
cond_resched();
+ }
}
static void o2net_listen_data_ready(struct sock *sk, int bytes)
_
More information about the Ocfs2-devel
mailing list