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From: James Chapman <jchapman@katalix•com>
To: Jarek Poplawski <jarkao2@gmail•com>
Cc: David Miller <davem@davemloft•net>,
	Paul Mackerras <paulus@samba•org>,
	netdev@vger•kernel.org
Subject: Re: [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver
Date: Mon, 25 Feb 2008 12:19:50 +0000	[thread overview]
Message-ID: <47C2B266.8070604@katalix.com> (raw)
In-Reply-To: <47BDB030.1050105@gmail.com>

[-- Attachment #1: Type: text/plain, Size: 960 bytes --]

Jarek Poplawski wrote:
> Jarek Poplawski wrote, On 02/21/2008 01:08 PM:
> ...
> 
>> Another, probably simpler way would be to move almost all pppol2tp_xmit
> ...
> 
> Actually, the simplest off all seems to be now this old idea to maybe make
> sk_dst_lock globally softirq immune. At least I think it's worth of testing,
> to check for these other possible lockdep warnings. It should only need to
> change all write_ and read_lock(&sk->sk_dst_lock) in very few places:
> include/net/sock.h, include/net/ip6_route.h, and net/ipv6/ipv6_sockglue.c.
> This could be tested together with you full _bh locking patch (maybe except
> these other changes in pppol2tp_xmit).

I did this and all lockdep errors have now gone. Tests ran all weekend. 
See attached patch.

Is this an acceptable solution? If so, I'll prepare and send official 
patches.


-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
Catalysts for your Embedded Linux software development


[-- Attachment #2: sk_dst_lock-softirq-safe.patch --]
[-- Type: text/x-diff, Size: 2648 bytes --]

Index: linux-2.6.24.2/include/net/ip6_route.h
===================================================================
--- linux-2.6.24.2.orig/include/net/ip6_route.h
+++ linux-2.6.24.2/include/net/ip6_route.h
@@ -150,9 +150,9 @@ static inline void __ip6_dst_store(struc
 static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
 				 struct in6_addr *daddr, struct in6_addr *saddr)
 {
-	write_lock(&sk->sk_dst_lock);
+	write_lock_bh(&sk->sk_dst_lock);
 	__ip6_dst_store(sk, dst, daddr, saddr);
-	write_unlock(&sk->sk_dst_lock);
+	write_unlock_bh(&sk->sk_dst_lock);
 }
 
 static inline int ipv6_unicast_destination(struct sk_buff *skb)
Index: linux-2.6.24.2/include/net/sock.h
===================================================================
--- linux-2.6.24.2.orig/include/net/sock.h
+++ linux-2.6.24.2/include/net/sock.h
@@ -1058,11 +1058,11 @@ sk_dst_get(struct sock *sk)
 {
 	struct dst_entry *dst;
 
-	read_lock(&sk->sk_dst_lock);
+	read_lock_bh(&sk->sk_dst_lock);
 	dst = sk->sk_dst_cache;
 	if (dst)
 		dst_hold(dst);
-	read_unlock(&sk->sk_dst_lock);
+	read_unlock_bh(&sk->sk_dst_lock);
 	return dst;
 }
 
@@ -1079,9 +1079,9 @@ __sk_dst_set(struct sock *sk, struct dst
 static inline void
 sk_dst_set(struct sock *sk, struct dst_entry *dst)
 {
-	write_lock(&sk->sk_dst_lock);
+	write_lock_bh(&sk->sk_dst_lock);
 	__sk_dst_set(sk, dst);
-	write_unlock(&sk->sk_dst_lock);
+	write_unlock_bh(&sk->sk_dst_lock);
 }
 
 static inline void
@@ -1097,9 +1097,9 @@ __sk_dst_reset(struct sock *sk)
 static inline void
 sk_dst_reset(struct sock *sk)
 {
-	write_lock(&sk->sk_dst_lock);
+	write_lock_bh(&sk->sk_dst_lock);
 	__sk_dst_reset(sk);
-	write_unlock(&sk->sk_dst_lock);
+	write_unlock_bh(&sk->sk_dst_lock);
 }
 
 extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
Index: linux-2.6.24.2/net/ipv6/ipv6_sockglue.c
===================================================================
--- linux-2.6.24.2.orig/net/ipv6/ipv6_sockglue.c
+++ linux-2.6.24.2/net/ipv6/ipv6_sockglue.c
@@ -440,9 +440,9 @@ static int do_ipv6_setsockopt(struct soc
 			opt = xchg(&np->opt, opt);
 			sk_dst_reset(sk);
 		} else {
-			write_lock(&sk->sk_dst_lock);
+			write_lock_bh(&sk->sk_dst_lock);
 			opt = xchg(&np->opt, opt);
-			write_unlock(&sk->sk_dst_lock);
+			write_unlock_bh(&sk->sk_dst_lock);
 			sk_dst_reset(sk);
 		}
 sticky_done:
@@ -504,9 +504,9 @@ update:
 			opt = xchg(&np->opt, opt);
 			sk_dst_reset(sk);
 		} else {
-			write_lock(&sk->sk_dst_lock);
+			write_lock_bh(&sk->sk_dst_lock);
 			opt = xchg(&np->opt, opt);
-			write_unlock(&sk->sk_dst_lock);
+			write_unlock_bh(&sk->sk_dst_lock);
 			sk_dst_reset(sk);
 		}
 

  reply	other threads:[~2008-02-25 12:20 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-11  9:22 [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver James Chapman
2008-02-11 18:57 ` Jarek Poplawski
2008-02-11 22:19   ` James Chapman
2008-02-11 22:49     ` Jarek Poplawski
2008-02-11 22:55       ` Jarek Poplawski
2008-02-11 23:42         ` James Chapman
2008-02-12 10:42           ` Jarek Poplawski
2008-02-11 23:41       ` James Chapman
2008-02-12  5:30         ` David Miller
2008-02-12 10:58           ` James Chapman
2008-02-12 13:24             ` Jarek Poplawski
2008-02-13  6:00             ` David Miller
2008-02-13  7:29               ` Jarek Poplawski
2008-02-14 13:00             ` Jarek Poplawski
2008-02-18 22:09               ` James Chapman
2008-02-18 23:01                 ` Jarek Poplawski
2008-02-19  9:09                   ` James Chapman
2008-02-19  4:29                 ` David Miller
2008-02-19  9:03                   ` James Chapman
2008-02-19 10:30                     ` Jarek Poplawski
2008-02-19 10:36                       ` Jarek Poplawski
2008-02-19 14:37                       ` James Chapman
2008-02-19 23:06                 ` Jarek Poplawski
2008-02-19 23:28                   ` Jarek Poplawski
2008-02-20 16:02                   ` James Chapman
2008-02-20 18:38                     ` Jarek Poplawski
2008-02-20 22:37                       ` James Chapman
2008-02-21  8:59                         ` Jarek Poplawski
2008-02-21  9:53                           ` James Chapman
2008-02-21 12:08                             ` Jarek Poplawski
2008-02-21 17:09                               ` Jarek Poplawski
2008-02-25 12:19                                 ` James Chapman [this message]
2008-02-25 13:05                                   ` Jarek Poplawski
2008-02-25 13:39                                     ` Jarek Poplawski
2008-02-25 14:02                                       ` Jarek Poplawski
2008-02-25 21:58                                       ` Jarek Poplawski
2008-02-26 12:14                                         ` James Chapman
2008-02-26 13:03                                           ` Jarek Poplawski
2008-02-26 13:18                                             ` Jarek Poplawski
2008-02-26 20:00                                           ` Jarek Poplawski
2008-03-02 20:29                                             ` James Chapman
2008-03-03  8:22                                               ` Jarek Poplawski
2008-03-03  9:35                                                 ` Jarek Poplawski
2008-02-27 10:54                                           ` [PATCH][PPPOL2TP] add missing sock_put() in pppol2tp_recv_dequeue() Jarek Poplawski
2008-03-02 20:31                                             ` James Chapman
2008-03-04  4:49                                               ` David Miller
2008-02-27 11:48                                           ` [PATCH][PPPOL2TP] add missing sock_put() in pppol2tp_tunnel_closeall() Jarek Poplawski
2008-03-02 20:32                                             ` James Chapman
2008-03-04  4:49                                               ` David Miller
2008-02-22 14:16                             ` [PATCH][NET] sock.c: sk_dst_lock lockdep keys and names per af_family Jarek Poplawski
2008-02-12  7:19         ` [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver Jarek Poplawski

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