From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, "Pasi K�rkk�inen" <pasik@iki.fi>,
"Eric Dumazet" <edumazet@google.com>,
"Neal Cardwell" <ncardwell@google.com>,
"Yuchung Cheng" <ycheng@google.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [ 53/61] tcp: fix an infinite loop in tcp_slow_start()
Date: Tue, 12 Feb 2013 12:35:13 -0800 [thread overview]
Message-ID: <20130212203425.027018012@linuxfoundation.org> (raw)
In-Reply-To: <20130212203417.890993903@linuxfoundation.org>
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3.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 973ec449bb4f2b8c514bacbcb4d9506fc31c8ce3 ]
Since commit 9dc274151a548 (tcp: fix ABC in tcp_slow_start()),
a nul snd_cwnd triggers an infinite loop in tcp_slow_start()
Avoid this infinite loop and log a one time error for further
analysis. FRTO code is suspected to cause this bug.
Reported-by: Pasi Kärkkäinen <pasik@iki.fi>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/tcp_cong.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -309,6 +309,12 @@ void tcp_slow_start(struct tcp_sock *tp)
{
int cnt; /* increase in packets */
unsigned int delta = 0;
+ u32 snd_cwnd = tp->snd_cwnd;
+
+ if (unlikely(!snd_cwnd)) {
+ pr_err_once("snd_cwnd is nul, please report this bug.\n");
+ snd_cwnd = 1U;
+ }
/* RFC3465: ABC Slow start
* Increase only after a full MSS of bytes is acked
@@ -323,7 +329,7 @@ void tcp_slow_start(struct tcp_sock *tp)
if (sysctl_tcp_max_ssthresh > 0 && tp->snd_cwnd > sysctl_tcp_max_ssthresh)
cnt = sysctl_tcp_max_ssthresh >> 1; /* limited slow start */
else
- cnt = tp->snd_cwnd; /* exponential increase */
+ cnt = snd_cwnd; /* exponential increase */
/* RFC3465: ABC
* We MAY increase by 2 if discovered delayed ack
@@ -333,11 +339,11 @@ void tcp_slow_start(struct tcp_sock *tp)
tp->bytes_acked = 0;
tp->snd_cwnd_cnt += cnt;
- while (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
- tp->snd_cwnd_cnt -= tp->snd_cwnd;
+ while (tp->snd_cwnd_cnt >= snd_cwnd) {
+ tp->snd_cwnd_cnt -= snd_cwnd;
delta++;
}
- tp->snd_cwnd = min(tp->snd_cwnd + delta, tp->snd_cwnd_clamp);
+ tp->snd_cwnd = min(snd_cwnd + delta, tp->snd_cwnd_clamp);
}
EXPORT_SYMBOL_GPL(tcp_slow_start);
next prev parent reply other threads:[~2013-02-12 20:36 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-12 20:34 [ 00/61] 3.7.8-stable review Greg Kroah-Hartman
2013-02-12 20:34 ` [ 01/61] rtlwifi: Fix the usage of the wrong variable in usb.c Greg Kroah-Hartman
2013-02-12 20:34 ` [ 02/61] rtlwifi: Fix scheduling while atomic bug Greg Kroah-Hartman
2013-02-12 20:34 ` [ 03/61] regulator: max8998: fix incorrect min_uV value for ldo10 Greg Kroah-Hartman
2013-02-12 20:34 ` [ 04/61] regulator: clear state each invocation of of_regulator_match Greg Kroah-Hartman
2013-02-12 20:34 ` [ 05/61] regulator: s2mps11: fix incorrect register for buck10 Greg Kroah-Hartman
2013-02-12 20:34 ` [ 06/61] IB/qib: Fix for broken sparse warning fix Greg Kroah-Hartman
2013-02-12 20:34 ` [ 07/61] virtio_console: Dont access uninitialized data Greg Kroah-Hartman
2013-02-12 20:34 ` [ 08/61] Bluetooth: Fix handling of unexpected SMP PDUs Greg Kroah-Hartman
2013-02-12 20:34 ` [ 09/61] Revert "iwlwifi: fix the reclaimed packet tracking upon flush queue" Greg Kroah-Hartman
2013-02-12 20:34 ` [ 10/61] can: c_can: Set reserved bit in IFx_MASK2 to 1 on write Greg Kroah-Hartman
2013-02-12 20:34 ` [ 11/61] mwifiex: fix incomplete scan in case of IE parsing error Greg Kroah-Hartman
2013-02-12 20:34 ` [ 12/61] e1000e: enable ECC on I217/I218 to catch packet buffer memory errors Greg Kroah-Hartman
2013-02-12 20:34 ` [ 13/61] media: pwc-if: must check vb2_queue_init() success Greg Kroah-Hartman
2013-02-12 20:34 ` [ 14/61] ath9k_hw: fix calibration issues on chainmask that dont include chain 0 Greg Kroah-Hartman
2013-02-12 20:34 ` [ 15/61] mfd: db8500-prcmu: Fix irqdomain usage Greg Kroah-Hartman
2013-02-12 20:34 ` [ 16/61] dm thin: fix queue limits stacking Greg Kroah-Hartman
2013-02-12 20:34 ` [ 17/61] net: prevent setting ttl=0 via IP_TTL Greg Kroah-Hartman
2013-02-12 20:34 ` [ 18/61] ipv6: fix the noflags test in addrconf_get_prefix_route Greg Kroah-Hartman
2013-02-12 20:34 ` [ 19/61] net, wireless: overwrite default_ethtool_ops Greg Kroah-Hartman
2013-02-12 20:34 ` [ 20/61] tcp: fix a panic on UP machines in reqsk_fastopen_remove Greg Kroah-Hartman
2013-02-12 20:34 ` [ 21/61] MAINTAINERS: Stephen Hemminger email change Greg Kroah-Hartman
2013-02-12 20:34 ` [ 22/61] ipv6: fix header length calculation in ip6_append_data() Greg Kroah-Hartman
2013-02-12 20:34 ` [ 23/61] macvlan: fix macvlan_get_size() Greg Kroah-Hartman
2013-02-12 20:34 ` [ 24/61] net: calxedaxgmac: throw away overrun frames Greg Kroah-Hartman
2013-02-12 20:34 ` [ 25/61] net/mlx4_en: Fix bridged vSwitch configuration for non SRIOV mode Greg Kroah-Hartman
2013-02-12 20:34 ` [ 26/61] net/mlx4_core: Set number of msix vectors under SRIOV mode to firmware defaults Greg Kroah-Hartman
2013-02-12 20:34 ` [ 27/61] tcp: fix incorrect LOCKDROPPEDICMPS counter Greg Kroah-Hartman
2013-02-12 20:34 ` [ 28/61] isdn/gigaset: fix zero size border case in debug dump Greg Kroah-Hartman
2013-02-12 20:34 ` [ 29/61] netxen: fix off by one bug in netxen_release_tx_buffer() Greg Kroah-Hartman
2013-02-12 20:34 ` [ 30/61] r8169: remove the obsolete and incorrect AMD workaround Greg Kroah-Hartman
2013-02-12 20:34 ` [ 31/61] net: loopback: fix a dst refcounting issue Greg Kroah-Hartman
2013-02-12 20:34 ` [ 32/61] IP_GRE: Fix kernel panic in IP_GRE with GRE csum Greg Kroah-Hartman
2013-02-12 20:34 ` [ 33/61] pktgen: correctly handle failures when adding a device Greg Kroah-Hartman
2013-02-12 20:34 ` [ 34/61] ipv6: do not create neighbor entries for local delivery Greg Kroah-Hartman
2013-02-12 20:34 ` [ 35/61] via-rhine: Fix bugs in NAPI support Greg Kroah-Hartman
2013-02-12 20:34 ` [ 36/61] packet: fix leakage of tx_ring memory Greg Kroah-Hartman
2013-02-12 20:34 ` [ 37/61] ipv6/ip6_gre: fix error case handling in ip6gre_tunnel_xmit() Greg Kroah-Hartman
2013-02-12 20:34 ` [ 38/61] atm/iphase: rename fregt_t -> ffreg_t Greg Kroah-Hartman
2013-02-12 20:34 ` [ 39/61] xen/netback: shutdown the ring if it contains garbage Greg Kroah-Hartman
2013-02-12 20:35 ` [ 40/61] xen/netback: dont leak pages on failure in xen_netbk_tx_check_gop Greg Kroah-Hartman
2013-02-12 20:35 ` [ 41/61] xen/netback: free already allocated memory on failure in xen_netbk_get_requests Greg Kroah-Hartman
2013-02-12 20:35 ` [ 42/61] netback: correct netbk_tx_err to handle wrap around Greg Kroah-Hartman
2013-02-12 20:35 ` [ 43/61] ipv4: Remove output route check in ipv4_mtu Greg Kroah-Hartman
2013-02-12 20:35 ` [ 44/61] ipv4: Dont update the pmtu on mtu locked routes Greg Kroah-Hartman
2013-02-12 20:35 ` [ 45/61] ipv6: Add an error handler for icmp6 Greg Kroah-Hartman
2013-02-12 20:35 ` [ 46/61] ipv4: Invalidate the socket cached route on pmtu events if possible Greg Kroah-Hartman
2013-02-12 20:35 ` [ 47/61] ipv4: Add a socket release callback for datagram sockets Greg Kroah-Hartman
2013-02-12 20:35 ` [ 48/61] ipv4: Fix route refcount on pmtu discovery Greg Kroah-Hartman
2013-02-12 20:35 ` [ 49/61] sctp: refactor sctp_outq_teardown to insure proper re-initalization Greg Kroah-Hartman
2013-02-12 20:35 ` [ 50/61] net: sctp: sctp_setsockopt_auth_key: use kzfree instead of kfree Greg Kroah-Hartman
2013-02-12 20:35 ` [ 51/61] net: sctp: sctp_endpoint_free: zero out secret key data Greg Kroah-Hartman
2013-02-12 20:35 ` [ 52/61] tcp: detect SYN/data drop when F-RTO is disabled Greg Kroah-Hartman
2013-02-12 20:35 ` Greg Kroah-Hartman [this message]
2013-02-12 20:35 ` [ 54/61] tcp: frto should not set snd_cwnd to 0 Greg Kroah-Hartman
2013-02-12 20:35 ` [ 55/61] tcp: fix for zero packets_in_flight was too broad Greg Kroah-Hartman
2013-02-12 20:35 ` [ 56/61] tcp: dont abort splice() after small transfers Greg Kroah-Hartman
2013-02-12 20:35 ` [ 57/61] tcp: splice: fix an infinite loop in tcp_read_sock() Greg Kroah-Hartman
2013-02-12 20:35 ` [ 58/61] tcp: fix splice() and tcp collapsing interaction Greg Kroah-Hartman
2013-02-12 20:35 ` [ 59/61] net: splice: avoid high order page splitting Greg Kroah-Hartman
2013-02-12 20:35 ` [ 60/61] net: splice: fix __splice_segment() Greg Kroah-Hartman
2013-02-12 20:35 ` [ 61/61] drm/nouveau: add lockdep annotations Greg Kroah-Hartman
2013-02-13 3:35 ` Peter Hurley
2013-02-13 9:33 ` Arend van Spriel
2013-02-13 9:43 ` Ben Skeggs
2013-02-13 9:52 ` Arend van Spriel
2013-02-13 17:46 ` Marcin Slusarz
2013-02-13 18:38 ` Marcin Slusarz
2013-02-13 7:06 ` [ 00/61] 3.7.8-stable review Satoru Takeuchi
2013-02-13 15:51 ` Shuah Khan
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