From: Denis V. Lunev Date: Sat, 23 Aug 2008 11:43:33 +0000 (-0700) Subject: icmp: icmp_sk() should not use smp_processor_id() in preemptible code X-Git-Tag: v2.6.27-rc5~42^2~1 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fdc0bde90a689b9145f2b6f271c03f4c99d09667;p=linux-2.6 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 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: [] debug_smp_processor_id+0xe4/0xf0 [] icmp_sk+0x15/0x30 [] icmp_send+0x4b/0x3f0 [] ? trace_hardirqs_on_caller+0xd5/0x160 [] ? trace_hardirqs_on+0xd/0x10 [] ? local_bh_enable_ip+0x95/0x110 [] ? _spin_unlock_bh+0x39/0x40 [] ? mark_held_locks+0x4c/0x90 [] ? trace_hardirqs_on+0xd/0x10 [] ? trace_hardirqs_on_caller+0xd5/0x160 [] ip_fragment+0x8d4/0x900 [] ? ip_finish_output2+0x0/0x290 [] ? ip_finish_output+0x0/0x60 [] ? dst_output+0x0/0x10 [] ip_finish_output+0x4c/0x60 [] ip_output+0xa3/0xf0 [] ip_local_out+0x20/0x30 [] ip_push_pending_frames+0x27f/0x400 [] udp_push_pending_frames+0x233/0x3d0 [] udp_sendmsg+0x321/0x6f0 [] inet_sendmsg+0x45/0x80 [] sock_sendmsg+0xdf/0x110 [] ? autoremove_wake_function+0x0/0x40 [] ? validate_chain+0x415/0x1010 [] ? __do_fault+0x140/0x450 [] ? __lock_acquire+0x260/0x590 [] ? sockfd_lookup_light+0x45/0x80 [] sys_sendto+0xea/0x120 [] ? _spin_unlock_irqrestore+0x42/0x80 [] ? __up_read+0x4c/0xb0 [] ? up_read+0x26/0x30 [] system_call_fastpath+0x16/0x1b icmp6_sk() is similar. Signed-off-by: Denis V. Lunev Signed-off-by: David S. Miller --- diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 860558633b..55c355e632 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -204,18 +204,22 @@ static struct sock *icmp_sk(struct net *net) 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 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) 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 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) 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 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) } } - 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 abedf95fdf..b3157a0cc1 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -91,19 +91,22 @@ static struct inet6_protocol icmpv6_protocol = { .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 @@ void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info, 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 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 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;