This is a note to let you know that I've just added the patch titled
tcp: avoid a possible divide by zero
to the 2.6.36-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-avoid-a-possible-divide-by-zero.patch
and it can be found in the queue-2.6.36 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b6bd33114e63d96f424c8e2baf46b3a58745077b Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Tue, 7 Dec 2010 12:03:55 +0000
Subject: tcp: avoid a possible divide by zero
From: Eric Dumazet <[email protected]>
[ Upstream commit ad9f4f50fe9288bbe65b7dfd76d8820afac6a24c ]
sysctl_tcp_tso_win_divisor might be set to zero while one cpu runs in
tcp_tso_should_defer(). Make sure we dont allow a divide by zero by
reading sysctl_tcp_tso_win_divisor exactly once.
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/ipv4/tcp_output.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1518,6 +1518,7 @@ static int tcp_tso_should_defer(struct s
struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
u32 send_win, cong_win, limit, in_flight;
+ int win_divisor;
if (TCP_SKB_CB(skb)->flags & TCPHDR_FIN)
goto send_now;
@@ -1549,13 +1550,14 @@ static int tcp_tso_should_defer(struct s
if ((skb != tcp_write_queue_tail(sk)) && (limit >= skb->len))
goto send_now;
- if (sysctl_tcp_tso_win_divisor) {
+ win_divisor = ACCESS_ONCE(sysctl_tcp_tso_win_divisor);
+ if (win_divisor) {
u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache);
/* If at least some fraction of a window is available,
* just use it.
*/
- chunk /= sysctl_tcp_tso_win_divisor;
+ chunk /= win_divisor;
if (limit >= chunk)
goto send_now;
} else {
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.36/tcp-protect-sysctl_tcp_cookie_size-reads.patch
queue-2.6.36/tcp-don-t-change-unlocked-socket-state-in-tcp_v4_err.patch
queue-2.6.36/net-dst-dst_dev_event-called-after-other-notifiers.patch
queue-2.6.36/pppoe.c-fix-kernel-panic-caused-by-__pppoe_xmit.patch
queue-2.6.36/net-fix-skb_defer_rx_timestamp.patch
queue-2.6.36/filter-fix-sk_filter-rcu-handling.patch
queue-2.6.36/af_unix-limit-unix_tot_inflight.patch
queue-2.6.36/llc-fix-a-device-refcount-imbalance.patch
queue-2.6.36/af_unix-limit-recursion-level.patch
queue-2.6.36/tcp-avoid-a-possible-divide-by-zero.patch
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