icmp: icmp_sk() should not use smp_processor_id() in preemptible code
Pass namespace into icmp_xmit_lock, obtain socket inside and return
it as a result for caller.
Thanks Alexey Dobryan for this report:
Steps to reproduce:
CONFIG_PREEMPT=y
CONFIG_DEBUG_PREEMPT=y
tracepath <something>
BUG: using smp_processor_id() in preemptible [00000000] code: tracepath/3205
caller is icmp_sk+0x15/0x30
Pid: 3205, comm: tracepath Not tainted 2.6.27-rc4 #1
Call Trace:
[<ffffffff8031af14>] debug_smp_processor_id+0xe4/0xf0
[<ffffffff80409405>] icmp_sk+0x15/0x30
[<ffffffff8040a17b>] icmp_send+0x4b/0x3f0
[<ffffffff8025a415>] ? trace_hardirqs_on_caller+0xd5/0x160
[<ffffffff8025a4ad>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff8023a475>] ? local_bh_enable_ip+0x95/0x110
[<ffffffff804285b9>] ? _spin_unlock_bh+0x39/0x40
[<ffffffff8025a26c>] ? mark_held_locks+0x4c/0x90
[<ffffffff8025a4ad>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff8025a415>] ? trace_hardirqs_on_caller+0xd5/0x160
[<ffffffff803e91b4>] ip_fragment+0x8d4/0x900
[<ffffffff803e7030>] ? ip_finish_output2+0x0/0x290
[<ffffffff803e91e0>] ? ip_finish_output+0x0/0x60
[<ffffffff803e6650>] ? dst_output+0x0/0x10
[<ffffffff803e922c>] ip_finish_output+0x4c/0x60
[<ffffffff803e92e3>] ip_output+0xa3/0xf0
[<ffffffff803e68d0>] ip_local_out+0x20/0x30
[<ffffffff803e753f>] ip_push_pending_frames+0x27f/0x400
[<ffffffff80406313>] udp_push_pending_frames+0x233/0x3d0
[<ffffffff804067d1>] udp_sendmsg+0x321/0x6f0
[<ffffffff8040d155>] inet_sendmsg+0x45/0x80
[<ffffffff803b967f>] sock_sendmsg+0xdf/0x110
[<ffffffff8024a100>] ? autoremove_wake_function+0x0/0x40
[<ffffffff80257ce5>] ? validate_chain+0x415/0x1010
[<ffffffff8027dc10>] ? __do_fault+0x140/0x450
[<ffffffff802597d0>] ? __lock_acquire+0x260/0x590
[<ffffffff803b9e55>] ? sockfd_lookup_light+0x45/0x80
[<ffffffff803ba50a>] sys_sendto+0xea/0x120
[<ffffffff80428e42>] ? _spin_unlock_irqrestore+0x42/0x80
[<ffffffff803134bc>] ? __up_read+0x4c/0xb0
[<ffffffff8024e0c6>] ? up_read+0x26/0x30
[<ffffffff8020b8bb>] system_call_fastpath+0x16/0x1b
icmp6_sk() is similar.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 8605586..55c355e 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -204,18 +204,22 @@
return net->ipv4.icmp_sk[smp_processor_id()];
}
-static inline int icmp_xmit_lock(struct sock *sk)
+static inline struct sock *icmp_xmit_lock(struct net *net)
{
+ struct sock *sk;
+
local_bh_disable();
+ sk = icmp_sk(net);
+
if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
/* This can happen if the output path signals a
* dst_link_failure() for an outgoing ICMP packet.
*/
local_bh_enable();
- return 1;
+ return NULL;
}
- return 0;
+ return sk;
}
static inline void icmp_xmit_unlock(struct sock *sk)
@@ -354,15 +358,17 @@
struct ipcm_cookie ipc;
struct rtable *rt = skb->rtable;
struct net *net = dev_net(rt->u.dst.dev);
- struct sock *sk = icmp_sk(net);
- struct inet_sock *inet = inet_sk(sk);
+ struct sock *sk;
+ struct inet_sock *inet;
__be32 daddr;
if (ip_options_echo(&icmp_param->replyopts, skb))
return;
- if (icmp_xmit_lock(sk))
+ sk = icmp_xmit_lock(net);
+ if (sk == NULL)
return;
+ inet = inet_sk(sk);
icmp_param->data.icmph.checksum = 0;
@@ -419,7 +425,6 @@
if (!rt)
goto out;
net = dev_net(rt->u.dst.dev);
- sk = icmp_sk(net);
/*
* Find the original header. It is expected to be valid, of course.
@@ -483,7 +488,8 @@
}
}
- if (icmp_xmit_lock(sk))
+ sk = icmp_xmit_lock(net);
+ if (sk == NULL)
return;
/*
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index abedf95..b3157a0 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -91,19 +91,22 @@
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
-static __inline__ int icmpv6_xmit_lock(struct sock *sk)
+static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
{
+ struct sock *sk;
+
local_bh_disable();
+ sk = icmpv6_sk(net);
if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
/* This can happen if the output path (f.e. SIT or
* ip6ip6 tunnel) signals dst_link_failure() for an
* outgoing ICMP6 packet.
*/
local_bh_enable();
- return 1;
+ return NULL;
}
- return 0;
+ return sk;
}
static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
@@ -392,11 +395,10 @@
fl.fl_icmp_code = code;
security_skb_classify_flow(skb, &fl);
- sk = icmpv6_sk(net);
- np = inet6_sk(sk);
-
- if (icmpv6_xmit_lock(sk))
+ sk = icmpv6_xmit_lock(net);
+ if (sk == NULL)
return;
+ np = inet6_sk(sk);
if (!icmpv6_xrlim_allow(sk, type, &fl))
goto out;
@@ -539,11 +541,10 @@
fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
security_skb_classify_flow(skb, &fl);
- sk = icmpv6_sk(net);
- np = inet6_sk(sk);
-
- if (icmpv6_xmit_lock(sk))
+ sk = icmpv6_xmit_lock(net);
+ if (sk == NULL)
return;
+ np = inet6_sk(sk);
if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
fl.oif = np->mcast_oif;
