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ip_dev_find(net, addr) finds a device given an IPv4 source address and
takes a reference on it.
Introduce __ip_dev_find(), taking a third argument, to optionally take
the device reference. Callers not asking the reference to be taken
should be in an rcu_read_lock() protected section.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While doing stress tests with a disabled IP route cache, I found
__mkroute_output() was touching three times in_device atomic refcount.
Use RCU to touch it once to reduce cache line ping pongs.
Before patch
time to perform the test
real 1m42.009s
user 0m12.545s
sys 25m0.726s
Profile :
16109.00 26.4% ip_route_output_slow vmlinux
7434.00 12.2% dst_destroy vmlinux
3280.00 5.4% fib_rules_lookup vmlinux
3252.00 5.3% fib_semantic_match vmlinux
2622.00 4.3% fib_table_lookup vmlinux
2535.00 4.1% dst_alloc vmlinux
1750.00 2.9% _raw_read_lock vmlinux
1532.00 2.5% rt_set_nexthop vmlinux
After patch
real 1m36.503s
user 0m12.977s
sys 23m25.608s
14234.00 22.4% ip_route_output_slow vmlinux
8717.00 13.7% dst_destroy vmlinux
4052.00 6.4% fib_rules_lookup vmlinux
3951.00 6.2% fib_semantic_match vmlinux
3191.00 5.0% dst_alloc vmlinux
1764.00 2.8% fib_table_lookup vmlinux
1692.00 2.7% _raw_read_lock vmlinux
1605.00 2.5% rt_set_nexthop vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
HARD_TX_LOCK no longer protects tunnels from dead loops,
but xmit_recursion percpu counter.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPIP tunnels can benefit from lockless xmits, using NETIF_F_LLTX
Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending
10000000 UDP frames via one ipip tunnel (size:200 bytes per frame)
Before patch :
real 2m53.321s
user 0m10.277s
sys 46m0.597s
After patch:
real 0m32.063s
user 0m9.237s
sys 8m16.255s
Last problem to solve is the contention on dst :
16118.00 28.3% __ip_route_output_key vmlinux
6135.00 10.8% dst_release vmlinux
3220.00 5.6% ip_finish_output vmlinux
2149.00 3.8% ip_route_output_flow vmlinux
1575.00 2.8% ip_append_data vmlinux
1481.00 2.6% ip_push_pending_frames vmlinux
1349.00 2.4% __xfrm_lookup vmlinux
1216.00 2.1% csum_partial_copy_generic vmlinux
1208.00 2.1% udp_sendmsg vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
GRE tunnels can benefit from lockless xmits, using NETIF_F_LLTX
Note: If tunnels are created with the "oseq" option, LLTX is not
enabled :
Even using an atomic_t o_seq, we would increase chance for packets being
out of order at receiver.
Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending
10000000 UDP frames via one gre tunnel (size:200 bytes per frame)
Before patch :
real 3m0.094s
user 0m9.365s
sys 47m50.103s
After patch:
real 0m29.756s
user 0m11.097s
sys 7m33.012s
Last problem to solve is the contention on dst :
38660.00 21.4% __ip_route_output_key vmlinux
20786.00 11.5% dst_release vmlinux
14191.00 7.8% __xfrm_lookup vmlinux
12410.00 6.9% ip_finish_output vmlinux
4540.00 2.5% ip_push_pending_frames vmlinux
4427.00 2.4% ip_append_data vmlinux
4265.00 2.4% __alloc_skb vmlinux
4140.00 2.3% __ip_local_out vmlinux
3991.00 2.2% dev_queue_xmit vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 3c97af99a5 (ipip: percpu stats accounting) forgot the fallback
tunnel case (tunl0), and can crash pretty fast.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows a host to be configured to respond to any address in
a specified range as if it were local, without actually needing to
configure the address on an interface. This is done through routing
table configuration. For instance, to configure a host to respond
to any address in 10.1/16 received on eth0 as a local address we can do:
ip rule add from all iif eth0 lookup 200
ip route add local 10.1/16 dev lo proto kernel scope host src 127.0.0.1 table 200
This host is now reachable by any 10.1/16 address (route lookup on
input for packets received on eth0 can find the route). On output, the
rule will not be matched so that this host can still send packets to
10.1/16 (not sent on loopback). Presumably, external routing can be
configured to make sense out of this.
To make this work, we needed to modify the logic in finding the
interface which is assigned a given source address for output
(dev_ip_find). We perform a normal fib_lookup instead of just a
lookup on the local table, and in the lookup we ignore the input
interface for matching.
This patch is useful to implement IP-anycast for subnets of virtual
addresses.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Maintain per_cpu tx_bytes, tx_packets, rx_bytes, rx_packets.
Other seldom used fields are kept in netdev->stats structure, possibly
unsafe.
This is a preliminary work to support lockless transmit path, and
correct RX stats, that are already unsafe.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Le lundi 27 septembre 2010 à 14:29 +0100, Ben Hutchings a écrit :
> > diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> > index 5d6ddcb..de39b22 100644
> > --- a/net/ipv4/ip_gre.c
> > +++ b/net/ipv4/ip_gre.c
> [...]
> > @@ -377,7 +405,7 @@ static struct ip_tunnel *ipgre_tunnel_locate(struct net *net,
> > if (parms->name[0])
> > strlcpy(name, parms->name, IFNAMSIZ);
> > else
> > - sprintf(name, "gre%%d");
> > + strcpy(name, "gre%d");
> >
> > dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
> > if (!dev)
> [...]
>
> This is a valid fix, but doesn't belong in this patch!
>
Sorry ? It was not a fix, but at most a cleanup ;)
Anyway I forgot the gretap case...
[PATCH 2/4 v2] ip_gre: percpu stats accounting
Maintain per_cpu tx_bytes, tx_packets, rx_bytes, rx_packets.
Other seldom used fields are kept in netdev->stats structure, possibly
unsafe.
This is a preliminary work to support lockless transmit path, and
correct RX stats, that are already unsafe.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__in_dev_get_rtnl(dev_out) is called while RTNL is not held, thus
triggers a lockdep fault.
At this point, we only perform a raw test of dev_out->ip_ptr being NULL,
we dont need to make sure ip_ptr cant changed right after.
We can use rcu_dereference_raw() for this.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While investigating a bit, I found ip_fragment() slow path was taken
because ip_append_data() provides following layout for a send(MTU +
N*(MTU - 20)) syscall :
- one skb with 1500 (mtu) bytes
- N fragments of 1480 (mtu-20) bytes (before adding IP header)
last fragment gets 17 bytes of trail data because of following bit:
if (datalen == length + fraggap)
alloclen += rt->dst.trailer_len;
Then esp4 adds 16 bytes of data (while trailer_len is 17... hmm...
another bug ?)
In ip_fragment(), we notice last fragment is too big (1496 + 20) > mtu,
so we take slow path, building another skb chain.
In order to avoid taking slow path, we should correct ip_append_data()
to make sure last fragment has real trail space, under mtu...
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change "return (EXPR);" to "return EXPR;"
return is not a function, parentheses are not required.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
otherwise ECT(1) bit will get interpreted as RTO_ONLINK
and routing will fail with XfrmOutBundleGenError.
Signed-off-by: Ulrich Weber <uweber@astaro.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
we need to check proper socket type within ipv4_conntrack_defrag
function before referencing the nodefrag flag.
For example the tun driver receive path produces skbs with
AF_UNSPEC socket type, and so current code is causing unwanted
fragmented packets going out.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix checksum calculation in nf_nat_snmp_basic.
Based on patches by Clark Wang <wtweeker@163.com> and
Stephen Hemminger <shemminger@vyatta.com>.
https://bugzilla.kernel.org/show_bug.cgi?id=17622
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_route_me_harder can't create the route cache when the outdev is the same
with the indev for the skbs whichout a valid protocol set.
__mkroute_input functions has this check:
1998 if (skb->protocol != htons(ETH_P_IP)) {
1999 /* Not IP (i.e. ARP). Do not create route, if it is
2000 * invalid for proxy arp. DNAT routes are always valid.
2001 *
2002 * Proxy arp feature have been extended to allow, ARP
2003 * replies back to the same interface, to support
2004 * Private VLAN switch technologies. See arp.c.
2005 */
2006 if (out_dev == in_dev &&
2007 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2008 err = -EINVAL;
2009 goto cleanup;
2010 }
2011 }
This patch gives the new skb a valid protocol to bypass this check. In order
to make ipt_REJECT work with bridges, you also need to enable ip_forward.
This patch also fixes a regression. When we used skb_copy_expand(), we
didn't have this issue stated above, as the protocol was properly set.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Special care should be taken when slow path is hit in ip_fragment() :
When walking through frags, we transfert truesize ownership from skb to
frags. Then if we hit a slow_path condition, we must undo this or risk
uncharging frags->truesize twice, and in the end, having negative socket
sk_wmem_alloc counter, or even freeing socket sooner than expected.
Many thanks to Nick Bowler, who provided a very clean bug report and
test program.
Thanks to Jarek for reviewing my first patch and providing a V2
While Nick bisection pointed to commit 2b85a34e91 (net: No more
expensive sock_hold()/sock_put() on each tx), underlying bug is older
(2.6.12-rc5)
A side effect is to extend work done in commit b2722b1c3a
(ip_fragment: also adjust skb->truesize for packets not owned by a
socket) to ipv6 as well.
Reported-and-bisected-by: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a RST comes in immediately after checking sk->sk_err, tcp_poll will
return POLLIN but not POLLOUT. Fix this by checking sk->sk_err at the end
of tcp_poll. Additionally, ensure the correct order of operations on SMP
machines with memory barriers.
Signed-off-by: Tom Marshall <tdm.code@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The family parameter xfrm_state_find is used to find a state matching a
certain policy. This value is set to the template's family
(encap_family) right before xfrm_state_find is called.
The family parameter is however also used to construct a temporary state
in xfrm_state_find itself which is wrong for inter-family scenarios
because it produces a selector for the wrong family. Since this selector
is included in the xfrm_user_acquire structure, user space programs
misinterpret IPv6 addresses as IPv4 and vice versa.
This patch splits up the original init_tempsel function into a part that
initializes the selector respectively the props and id of the temporary
state, to allow for differing ip address families whithin the state.
Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Under load, netif_rx() can drop incoming packets but administrators dont
have a chance to spot which device needs some tuning (RPS activation for
example)
This patch adds rx_dropped accounting in vlans and tunnels.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6 can be a module, we should test CONFIG_IPV6 and CONFIG_IPV6_MODULE
to enable ipv6 bits in ip_gre.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Related dicussion here : http://lkml.org/lkml/2010/9/3/16
Introduce a function br_parse_ip_options that will audit the
skb and possibly refill IP options before a packet enters the
IP stack. If no options are present, the function will zero out
the skb cb area so that it is not misinterpreted as options by some
unsuspecting IP layer routine. If packet consistency fails, drop it.
Signed-off-by: Bandan Das <bandan.das@stratus.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
dev->ip_ptr is protected by rtnl and rcu.
Yet some places dont use appropriate primitives and/or locking rules.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As RTNL is held while doing tunnels inserts and deletes, we can remove
ipgre_lock spinlock. My initial RCU conversion was conservative and
converted the rwlock to spinlock, with no RTNL requirement.
Use appropriate rcu annotations and modern lockdep checks as well.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As RTNL is held while doing tunnels inserts and deletes, we can remove
ipip_lock spinlock. My initial RCU conversion was conservative and
converted the rwlock to spinlock, with no RTNL requirement.
Use appropriate rcu annotations and modern lockdep checks as well.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While integrating your man-pages patch for IP_NODEFRAG, I noticed
that this option is settable by setsockopt(), but not gettable by
getsockopt(). I suppose this is not intended. The (untested,
trivial) patch below adds getsockopt() support.
Signed-off-by: Michael kerrisk <mtk.manpages@gmail.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After all these years, it turns out that the
/proc/sys/net/ipv4/conf/*/force_igmp_version
parameter isn't fully implemented.
*Symptom*:
When set force_igmp_version to a value of 2, the kernel should only perform
multicast IGMPv2 operations (IETF rfc2236). An host-initiated Join message
will be sent as a IGMPv2 Join message. But if a IGMPv3 query message is
received, the host responds with a IGMPv3 join message. Per rfc3376 and
rfc2236, a IGMPv2 host should treat a IGMPv3 query as a IGMPv2 query and
respond with an IGMPv2 Join message.
*Consequences*:
This is an issue when a IGMPv3 capable switch is the querier and will only
issue IGMPv3 queries (which double as IGMPv2 querys) and there's an
intermediate switch that is only IGMPv2 capable. The intermediate switch
processes the initial v2 Join, but fails to recognize the IGMPv3 Join responses
to the Query, resulting in a dropped connection when the intermediate v2-only
switch times it out.
*Identifying issue in the kernel source*:
The issue is in this section of code (in net/ipv4/igmp.c), which is called when
an IGMP query is received (from mainline 2.6.36-rc3 gitweb):
...
A IGMPv3 query has a length >= 12 and no sources. This routine will exit after
line 880, setting the general query timer (random timeout between 0 and query
response time). This calls igmp_gq_timer_expire():
...
.. which only sends a v3 response. So if a v3 query is received, the kernel
always sends a v3 response.
IGMP queries happen once every 60 sec (per vlan), so the traffic is low. A
IGMPv3 query *is* a strict superset of a IGMPv2 query, so this patch properly
short circuit's the v3 behaviour.
One issue is that this does not address force_igmp_version=1. Then again, I've
never seen any IGMPv1 multicast equipment in the wild. However there is a lot
of v2-only equipment. If it's necessary to support the IGMPv1 case as well:
837 if (len == 8 || IGMP_V2_SEEN(in_dev) || IGMP_V1_SEEN(in_dev)) {
Signed-off-by: David S. Miller <davem@davemloft.net>
Use rcu_dereference_rtnl() helper
Change hard coded constants in fib_flag_trans()
7 -> RTN_UNREACHABLE
8 -> RTN_PROHIBIT
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xfrm4_tunnel_register() & xfrm6_tunnel_register() should
use rcu_assign_pointer() to make sure previous writes
(to handler->next) are committed to memory before chain
insertion.
deregister functions dont need a particular barrier.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 30fff923 introduced in linux-2.6.33 (udp: bind() optimisation)
added a secondary hash on UDP, hashed on (local addr, local port).
Problem is that following sequence :
fd = socket(...)
connect(fd, &remote, ...)
not only selects remote end point (address and port), but also sets
local address, while UDP stack stored in secondary hash table the socket
while its local address was INADDR_ANY (or ipv6 equivalent)
Sequence is :
- autobind() : choose a random local port, insert socket in hash tables
[while local address is INADDR_ANY]
- connect() : set remote address and port, change local address to IP
given by a route lookup.
When an incoming UDP frame comes, if more than 10 sockets are found in
primary hash table, we switch to secondary table, and fail to find
socket because its local address changed.
One solution to this problem is to rehash datagram socket if needed.
We add a new rehash(struct socket *) method in "struct proto", and
implement this method for UDP v4 & v6, using a common helper.
This rehashing only takes care of secondary hash table, since primary
hash (based on local port only) is not changed.
Reported-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use cmpxchg() to get rid of spinlocks in inet_add_protocol() and
friends.
inet_protos[] & inet6_protos[] are moved to read_mostly section
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Blackhole routes are used when xfrm_lookup() returns -EREMOTE (error
triggered by IKE for example), hence this kind of route is always
temporary and so we should check if a better route exists for next
packets.
Bug has been introduced by commit d11a4dc18b.
Signed-off-by: Jianzhao Wang <jianzhao.wang@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Actually iterate over the next-hops to make sure we have
a device match. Otherwise RP filtering is always elided
when the route matched has multiple next-hops.
Reported-by: Igor M Podlesny <for.poige@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clean the code up according to Documentation/CodingStyle.
Don't initialize the variable dont_send in arp_process().
Remove the temporary varialbe flags in arp_state_to_flags().
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Thanks to Ilpo Jarvinen, this updates also the initial window
setting for tcp_output with regard to RFC 5681.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
tunnel4_handlers, tunnel64_handlers, tunnel6_handlers and
tunnel46_handlers are protected by RCU, but we dont use appropriate rcu
primitives to scan them. rcu_lock() is already held by caller.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp4_gro_receive() and tcp4_gro_complete() dont need to be exported.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tunnel4_handlers chain being scanned for each incoming packet,
make sure it doesnt share an often dirtied cache line.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch consolidates initial-window code common to TCP and CCID-2:
* TCP uses RFC 3390 in a packet-oriented manner (tcp_input.c) and
* CCID-2 uses RFC 3390 in packet-oriented manner (RFC 4341).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch provides a "user timeout" support as described in RFC793. The
socket option is also needed for the the local half of RFC5482 "TCP User
Timeout Option".
TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int,
when > 0, to specify the maximum amount of time in ms that transmitted
data may remain unacknowledged before TCP will forcefully close the
corresponding connection and return ETIMEDOUT to the application. If
0 is given, TCP will continue to use the system default.
Increasing the user timeouts allows a TCP connection to survive extended
periods without end-to-end connectivity. Decreasing the user timeouts
allows applications to "fail fast" if so desired. Otherwise it may take
upto 20 minutes with the current system defaults in a normal WAN
environment.
The socket option can be made during any state of a TCP connection, but
is only effective during the synchronized states of a connection
(ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK).
Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option,
TCP_USER_TIMEOUT will overtake keepalive to determine when to close a
connection due to keepalive failure.
The option does not change in anyway when TCP retransmits a packet, nor
when a keepalive probe will be sent.
This option, like many others, will be inherited by an acceptor from its
listener.
Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The string clone is only used as a temporary copy of the argument val
within the while loop, and so it should be freed before leaving the
function. The call to strsep, however, modifies clone, so a pointer to the
front of the string is kept in saved_clone, to make it possible to free it.
The sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@r exists@
local idexpression x;
expression E;
identifier l;
statement S;
@@
*x= \(kasprintf\|kstrdup\)(...);
...
if (x == NULL) S
... when != kfree(x)
when != E = x
if (...) {
<... when != kfree(x)
* goto l;
...>
* return ...;
}
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This issue come from ruby language community. Below test program
hang up when only run on Linux.
% uname -mrsv
Linux 2.6.26-2-486 #1 Sat Dec 26 08:37:39 UTC 2009 i686
% ruby -rsocket -ve '
BasicSocket.do_not_reverse_lookup = true
serv = TCPServer.open("127.0.0.1", 0)
s1 = TCPSocket.open("127.0.0.1", serv.addr[1])
s2 = serv.accept
s2.close
s1.write("a") rescue p $!
s1.write("a") rescue p $!
Thread.new {
s1.write("a")
}.join'
ruby 1.9.3dev (2010-07-06 trunk 28554) [i686-linux]
#<Errno::EPIPE: Broken pipe>
[Hang Here]
FreeBSD, Solaris, Mac doesn't. because Ruby's write() method call
select() internally. and tcp_poll has a bug.
SUS defined 'ready for writing' of select() as following.
| A descriptor shall be considered ready for writing when a call to an output
| function with O_NONBLOCK clear would not block, whether or not the function
| would transfer data successfully.
That said, EPIPE situation is clearly one of 'ready for writing'.
We don't have read-side issue because tcp_poll() already has read side
shutdown care.
| if (sk->sk_shutdown & RCV_SHUTDOWN)
| mask |= POLLIN | POLLRDNORM | POLLRDHUP;
So, Let's insert same logic in write side.
- reference url
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/31065http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/31068
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
