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Date:   Fri, 16 Sep 2022 01:41:51 +0200
From:   Roberto Ricci <rroberto2r@gmail.com>
To:     Ido Schimmel <idosch@idosch.org>
Cc:     edumazet@google.com, davem@davemloft.net, yoshfuji@linux-ipv6.org,
        dsahern@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: BUG: unable to handle page fault for address, with ipv6.disable=1
Message-ID: <YyO4P50YeI0wlGM2@riccipc>
References: <YyD0kMC7qIBNOE3j@riccipc>
 <YyH3gBoUNT9yqrUx@shredder>
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On 2022-09-14 Wed 18:47:12 +0300, Ido Schimmel wrote:
> This is most likely caused by commit 0daf07e52709 ("raw: convert raw
> sockets to RCU") which is being back ported to stable kernels.
> 
> It made the initialization of 'raw_v6_hashinfo' conditional on IPv6
> being enabled. Can you try the following patch (works on my end)?
> 
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index 19732b5dce23..d40b7d60e00e 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -1072,13 +1072,13 @@ static int __init inet6_init(void)
>  	for (r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
>  		INIT_LIST_HEAD(r);
>  
> +	raw_hashinfo_init(&raw_v6_hashinfo);
> +
>  	if (disable_ipv6_mod) {
>  		pr_info("Loaded, but administratively disabled, reboot required to enable\n");
>  		goto out;
>  	}
>  
> -	raw_hashinfo_init(&raw_v6_hashinfo);
> -
>  	err = proto_register(&tcpv6_prot, 1);
>  	if (err)
>  		goto out;
> 
> Another approach is the following, but I prefer the first:
> 
> diff --git a/net/ipv4/raw_diag.c b/net/ipv4/raw_diag.c
> index 999321834b94..4fbdd69a2be8 100644
> --- a/net/ipv4/raw_diag.c
> +++ b/net/ipv4/raw_diag.c
> @@ -20,7 +20,7 @@ raw_get_hashinfo(const struct inet_diag_req_v2 *r)
>  	if (r->sdiag_family == AF_INET) {
>  		return &raw_v4_hashinfo;
>  #if IS_ENABLED(CONFIG_IPV6)
> -	} else if (r->sdiag_family == AF_INET6) {
> +	} else if (r->sdiag_family == AF_INET6 && ipv6_mod_enabled()) {
>  		return &raw_v6_hashinfo;
>  #endif
>  	} else {

Both the solutions you proposed work for me. Thanks.