Attachment 160770 Details for Bug 212922 – patch to avoid deadlock during sockopt unregister

[patch] patch to avoid deadlock during sockopt unregister

nf_sockopt_deadlock.patch (text/plain), 1.58 KB, created by Neil Horman on 2007-08-06 20:11:36 UTC

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Creator: Neil Horman

Created: 2007-08-06 20:11:36 UTC

Size: 1.58 KB

patch

obsolete

>--- linux-2.6.9/net/core/netfilter.c.orig	2007-08-06 14:04:42.000000000 -0400
>+++ linux-2.6.9/net/core/netfilter.c	2007-08-06 14:10:11.000000000 -0400
>@@ -48,6 +48,7 @@ static DECLARE_MUTEX(nf_sockopt_mutex);
> struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
> static LIST_HEAD(nf_sockopts);
> static spinlock_t nf_hook_lock = SPIN_LOCK_UNLOCKED;
>+static rwlock_t nf_use_lock = RW_LOCK_UNLOCKED;
> 
> /* 
>  * A queue handler may be registered for each protocol.  Each is protected by
>@@ -126,6 +127,7 @@ out:
> void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
> {
> 	/* No point being interruptible: we're probably in cleanup_module() */
>+	write_lock(&nf_use_lock);
>  restart:
> 	down(&nf_sockopt_mutex);
> 	if (reg->use != 0) {
>@@ -139,6 +141,7 @@ void nf_unregister_sockopt(struct nf_soc
> 	}
> 	list_del(&reg->list);
> 	up(&nf_sockopt_mutex);
>+	write_unlock(&nf_use_lock);
> }
> 
> #ifdef CONFIG_NETFILTER_DEBUG
>@@ -292,8 +295,12 @@ static int nf_sockopt(struct sock *sk, i
> 	struct nf_sockopt_ops *ops;
> 	int ret;
> 
>-	if (down_interruptible(&nf_sockopt_mutex) != 0)
>+	read_lock(&nf_use_lock);
>+
>+	if (down_interruptible(&nf_sockopt_mutex) != 0) {
>+		read_unlock(&use_lock);
> 		return -EINTR;
>+	}
> 
> 	list_for_each(i, &nf_sockopts) {
> 		ops = (struct nf_sockopt_ops *)i;
>@@ -318,6 +325,7 @@ static int nf_sockopt(struct sock *sk, i
> 		}
> 	}
> 	up(&nf_sockopt_mutex);
>+	read_unlock(&nf_use_lock);
> 	return -ENOPROTOOPT;
> 	
>  out:
>@@ -326,6 +334,7 @@ static int nf_sockopt(struct sock *sk, i
> 	if (ops->cleanup_task)
> 		wake_up_process(ops->cleanup_task);
> 	up(&nf_sockopt_mutex);
>+	read_unlock(&use_lock);
> 	return ret;
> }
>

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