netdev - Re: IPv4/IPv6 sysctl unregistration deadlock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <m1ab89m38q.fsf@fess.ebiederm.org>
Date:	Thu, 26 Feb 2009 11:01:41 -0800
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Stephen Hemminger <shemminger@...tta.com>
Cc:	Herbert Xu <herbert@...dor.apana.org.au>,
	Patrick McHardy <kaber@...sh.net>,
	Linux Netdev List <netdev@...r.kernel.org>,
	"David S. Miller" <davem@...emloft.net>
Subject: Re: IPv4/IPv6 sysctl unregistration deadlock

Stephen Hemminger <shemminger@...tta.com> writes:

> What about something like this:
>
> Subject: [PATCH] Avoid race between network down and sysfs

As far as solutions go.  That looks like the easiest correct solution.
So.  
Acked-by: "Eric W. Biederman" <ebiederm@...ssion.com>

Will -ERESTARTSYS trigger the in kernel restart logic in this case?

There are a lot more cases to cover, and I don't I like it long
term.  Spinning waiting for rtnl_lock feels wrong.  Plus it does
not help with discovering the problem in new sysfs, sysctl, or
proc files.

It has the major advantage that we can fix things now.

> Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
>
> --- a/net/core/net-sysfs.c	2009-02-26 08:36:18.000000000 -0800
> +++ b/net/core/net-sysfs.c	2009-02-26 08:37:51.000000000 -0800
> @@ -77,7 +77,9 @@ static ssize_t netdev_store(struct devic
>  	if (endp == buf)
>  		goto err;
>  
> -	rtnl_lock();
> +	if (!rtnl_trylock())
> +		return -ERESTARTSYS;
> +
>  	if (dev_isalive(net)) {
>  		if ((ret = (*set)(net, new)) == 0)
>  			ret = len;
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html