Commit 84427d53 authored by YOSHIFUJI Hideaki's avatar YOSHIFUJI Hideaki Committed by David S. Miller
Browse files

[IPV6]: Ensure to use icmpv6_socket in non-preemptive context. 



We saw following trace several times:

|BUG: using smp_processor_id() in preemptible [00000001] code: httpd/30137
|caller is icmpv6_send+0x23/0x540
| [<c01ad63b>] smp_processor_id+0x9b/0xb8
| [<c02993e7>] icmpv6_send+0x23/0x540

This is because of icmpv6_socket, which is the only one user of
smp_processor_id() in icmpv6_send(), AFAIK.

Since it should be used in non-preemptive context,
let's defer the dereference after disabling preemption
(by icmpv6_xmit_lock()).

Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 979b6c13

net/ipv6/icmp.c

+10 −4
Original line number Original line Diff line number Diff line
@@ -277,8 +277,8 @@ void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info, 
{

{

	struct inet6_dev *idev = NULL;

	struct inet6_dev *idev = NULL;

	struct ipv6hdr *hdr = skb->nh.ipv6h;

	struct ipv6hdr *hdr = skb->nh.ipv6h;

	struct sock *sk = icmpv6_socket->sk;

	struct sock *sk;

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_pinfo *np;

	struct in6_addr *saddr = NULL;

	struct in6_addr *saddr = NULL;

	struct dst_entry *dst;

	struct dst_entry *dst;

	struct icmp6hdr tmp_hdr;

	struct icmp6hdr tmp_hdr;
@@ -358,6 +358,9 @@ void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info, 
	if (icmpv6_xmit_lock())

	if (icmpv6_xmit_lock())

		return;

		return;





	sk = icmpv6_socket->sk;

	np = inet6_sk(sk);



	if (!icmpv6_xrlim_allow(sk, type, &fl))

	if (!icmpv6_xrlim_allow(sk, type, &fl))

		goto out;

		goto out;
@@ -423,9 +426,9 @@ out: 




static void icmpv6_echo_reply(struct sk_buff *skb)

static void icmpv6_echo_reply(struct sk_buff *skb)

{

{

	struct sock *sk = icmpv6_socket->sk;

	struct sock *sk;

	struct inet6_dev *idev;

	struct inet6_dev *idev;

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_pinfo *np;

	struct in6_addr *saddr = NULL;

	struct in6_addr *saddr = NULL;

	struct icmp6hdr *icmph = (struct icmp6hdr *) skb->h.raw;

	struct icmp6hdr *icmph = (struct icmp6hdr *) skb->h.raw;

	struct icmp6hdr tmp_hdr;

	struct icmp6hdr tmp_hdr;
@@ -454,6 +457,9 @@ static void icmpv6_echo_reply(struct sk_buff *skb) 
	if (icmpv6_xmit_lock())

	if (icmpv6_xmit_lock())

		return;

		return;





	sk = icmpv6_socket->sk;

	np = inet6_sk(sk);



	if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))

	if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))

		fl.oif = np->mcast_oif;

		fl.oif = np->mcast_oif;

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