From: Eric Dumazet <eric.dumazet@gmail.com>
To: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: David Miller <davem@davemloft.net>,
kunx.jiang@intel.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ipv4: fix the rcu race between free_fib_info and ip_route_output_slow
Date: Wed, 23 May 2012 07:02:19 +0200 [thread overview]
Message-ID: <1337749339.3361.1655.camel@edumazet-glaptop> (raw)
In-Reply-To: <1337748897.14538.184.camel@ymzhang.sh.intel.com>
On Wed, 2012-05-23 at 12:54 +0800, Yanmin Zhang wrote:
> > fi->fib_dev (aka fib_nh[0].nh_dev) need full RCU protection.
> The new patch posted at https://lkml.org/lkml/2012/5/22/558 does move the
> resetting to RCU protection.
Its not enough.
We must take care that all users are in a RCU protected region.
They might be already, but a full check is needed.
For example
net/ipv4/fib_trie.c:2563: fi->fib_dev ? fi->fib_dev->name : "*"
looks to be safe (because already in a rcu_read_lock())
But its not.
Right thing would be to do :
struct net_device *ndev = rcu_dereference(fi->fib_dev)
...
ndev ? ndev->name : "*"
next prev parent reply other threads:[~2012-05-23 5:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-22 9:48 [PATCH] ipv4: fix the rcu race between free_fib_info and ip_route_output_slow kun.jiang
2012-05-22 19:15 ` David Miller
2012-05-23 3:02 ` Yanmin Zhang
2012-05-23 3:23 ` David Miller
2012-05-23 3:30 ` Yanmin Zhang
2012-05-23 3:49 ` David Miller
2012-05-23 4:41 ` Yanmin Zhang
2012-05-23 5:08 ` Eric Dumazet
2012-05-23 4:37 ` Eric Dumazet
2012-05-23 4:54 ` Yanmin Zhang
2012-05-23 5:02 ` Eric Dumazet [this message]
2012-05-23 6:15 ` Yanmin Zhang
2012-05-23 6:27 ` Eric Dumazet
2012-05-23 6:47 ` Yanmin Zhang
2012-05-23 6:55 ` Eric Dumazet
2012-05-23 7:13 ` Eric Dumazet
2012-05-23 7:24 ` Yanmin Zhang
2012-05-23 7:39 ` Eric Dumazet
2012-05-23 7:41 ` Eric Dumazet
2012-05-23 7:47 ` Yanmin Zhang
2012-05-23 6:37 ` Eric Dumazet
2012-05-23 6:43 ` Eric Dumazet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1337749339.3361.1655.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=davem@davemloft.net \
--cc=kunx.jiang@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=yanmin_zhang@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox