From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: kuznet@ms2.inr.ac.ru, kaber@trash.net, equinox@diac24.net,
eparis@redhat.com, hzhong@gmail.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, pekkas@netcore.fi,
jmorris@namei.org, yoshfuji@linux-ipv6.org, paul.moore@hp.com,
damian@tvk.rwth-aachen.de
Subject: Re: a problem tcp_v4_err()
Date: Fri, 12 Nov 2010 13:36:20 -0800 (PST) [thread overview]
Message-ID: <20101112.133620.241452814.davem@davemloft.net> (raw)
In-Reply-To: <1289596718.2743.2.camel@edumazet-laptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 12 Nov 2010 22:18:38 +0100
> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Thanks for reviewing, here is the final bit I committed and
I'll queue this up for whatever -stable trees need this.
--------------------
tcp: Don't change unlocked socket state in tcp_v4_err().
Alexey Kuznetsov noticed a regression introduced by
commit f1ecd5d9e7366609d640ff4040304ea197fbc618
("Revert Backoff [v3]: Revert RTO on ICMP destination unreachable")
The RTO and timer modification code added to tcp_v4_err()
doesn't check sock_owned_by_user(), which if true means we
don't have exclusive access to the socket and therefore cannot
modify it's critical state.
Just skip this new code block if sock_owned_by_user() is true
and eliminate the now superfluous sock_owned_by_user() code
block contained within.
Reported-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
CC: Damian Lukowski <damian@tvk.rwth-aachen.de>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
---
net/ipv4/tcp_ipv4.c | 8 +++-----
1 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 8f8527d..69ccbc1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -415,6 +415,9 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
!icsk->icsk_backoff)
break;
+ if (sock_owned_by_user(sk))
+ break;
+
icsk->icsk_backoff--;
inet_csk(sk)->icsk_rto = __tcp_set_rto(tp) <<
icsk->icsk_backoff;
@@ -429,11 +432,6 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
if (remaining) {
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
remaining, TCP_RTO_MAX);
- } else if (sock_owned_by_user(sk)) {
- /* RTO revert clocked out retransmission,
- * but socket is locked. Will defer. */
- inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
- HZ/20, TCP_RTO_MAX);
} else {
/* RTO revert clocked out retransmission.
* Will retransmit now */
--
1.7.3.2
next prev parent reply other threads:[~2010-11-12 21:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 21:03 [RFC PATCH] network: return errors if we know tcp_connect failed Eric Paris
2010-11-11 21:14 ` Eric Dumazet
2010-11-11 21:58 ` Hua Zhong
2010-11-12 7:36 ` Patrick McHardy
2010-11-12 23:14 ` Hua Zhong
2010-11-15 10:32 ` Patrick McHardy
2010-11-15 15:47 ` Eric Paris
2010-11-15 15:57 ` Patrick McHardy
2010-11-15 16:04 ` Patrick McHardy
2010-11-15 16:36 ` Patrick McHardy
2010-11-15 16:46 ` David Miller
2010-11-15 20:00 ` Alexey Kuznetsov
2010-11-12 16:08 ` Eric Paris
2010-11-12 16:15 ` Eric Dumazet
2010-11-12 16:35 ` David Lamparter
2010-11-12 16:53 ` Eric Paris
2010-11-12 16:54 ` Patrick McHardy
2010-11-12 17:57 ` a problem tcp_v4_err() Alexey Kuznetsov
2010-11-12 18:12 ` Eric Dumazet
2010-11-12 18:21 ` Eric Dumazet
2010-11-12 18:27 ` Eric Dumazet
2010-11-12 18:31 ` Alexey Kuznetsov
2010-11-12 18:29 ` Alexey Kuznetsov
2010-11-12 18:33 ` Eric Dumazet
2010-11-12 19:22 ` David Miller
2010-11-12 21:18 ` Eric Dumazet
2010-11-12 21:36 ` David Miller [this message]
2010-11-12 21:16 ` [RFC PATCH] network: return errors if we know tcp_connect failed David Lamparter
2010-11-12 21:18 ` David Miller
2010-11-12 17:46 ` Alexey Kuznetsov
2010-11-12 19:28 ` David Miller
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