From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Christian Brauner <christian@brauner.io>,
Daniel Borkmann <daniel@iogearbox.net>,
David Ahern <dsahern@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Ingo Molnar <mingo@redhat.com>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Josh Triplett <josh@joshtriplett.org>,
keescook@chromium.org, kernel-hardening@lists.openwall.com,
kernel-team@android.com, Kirill Tkhai <ktkhai@virtuozzo.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Martin KaFai Lau <kafai@fb.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
netdev@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
Quentin Perret <quentin.perret@arm.com>,
rcu@vger.kernel.org, Song Liu <songliubraving@fb.com>,
Steven Rostedt <rostedt@goodmis.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
xdp-newbies@vger.kernel.org, Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH v2 1/6] net: rtnetlink: Fix incorrect RCU API usage
Date: Mon, 25 Feb 2019 13:05:51 -0800 [thread overview]
Message-ID: <20190225210551.GV4072@linux.ibm.com> (raw)
In-Reply-To: <20190223063434.6793-2-joel@joelfernandes.org>
On Sat, Feb 23, 2019 at 01:34:29AM -0500, Joel Fernandes (Google) wrote:
> rtnl_register_internal() and rtnl_unregister_all tries to directly
> dereference an RCU protected pointed outside RCU read side section.
> While this is Ok to do since a lock is held, let us use the correct
> API to avoid programmer bugs in the future.
>
> This also fixes sparse warnings arising from not using RCU API.
>
> net/core/rtnetlink.c:332:13: warning: incorrect type in assignment
> (different address spaces) net/core/rtnetlink.c:332:13: expected
> struct rtnl_link **tab net/core/rtnetlink.c:332:13: got struct
> rtnl_link *[noderef] <asn:4>*<noident>
>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
>From an RCU perspective:
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
> ---
> net/core/rtnetlink.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 5ea1bed08ede..98be4b4818a9 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -188,7 +188,7 @@ static int rtnl_register_internal(struct module *owner,
> msgindex = rtm_msgindex(msgtype);
>
> rtnl_lock();
> - tab = rtnl_msg_handlers[protocol];
> + tab = rtnl_dereference(rtnl_msg_handlers[protocol]);
> if (tab == NULL) {
> tab = kcalloc(RTM_NR_MSGTYPES, sizeof(void *), GFP_KERNEL);
> if (!tab)
> @@ -329,7 +329,7 @@ void rtnl_unregister_all(int protocol)
> BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX);
>
> rtnl_lock();
> - tab = rtnl_msg_handlers[protocol];
> + tab = rtnl_dereference(rtnl_msg_handlers[protocol]);
> if (!tab) {
> rtnl_unlock();
> return;
> --
> 2.21.0.rc0.258.g878e2cd30e-goog
>
next prev parent reply other threads:[~2019-02-25 21:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-23 6:34 [PATCH v2 0/6] RCU fixes for rcu_assign_pointer() usage Joel Fernandes (Google)
2019-02-23 6:34 ` [PATCH v2 1/6] net: rtnetlink: Fix incorrect RCU API usage Joel Fernandes (Google)
2019-02-25 21:05 ` Paul E. McKenney [this message]
2019-02-23 6:34 ` [PATCH v2 2/6] ixgbe: " Joel Fernandes (Google)
2019-02-25 21:09 ` Paul E. McKenney
2019-02-23 6:34 ` [PATCH v2 3/6] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu Joel Fernandes (Google)
2019-02-25 21:10 ` Paul E. McKenney
2019-02-27 15:42 ` Joel Fernandes
2019-02-23 6:34 ` [PATCH v2 4/6] sched_domain: Annotate RCU pointers properly Joel Fernandes (Google)
2019-02-25 21:11 ` Paul E. McKenney
2019-02-23 6:34 ` [PATCH v2 5/6] rcuwait: Annotate task_struct with __rcu Joel Fernandes (Google)
2019-02-25 21:11 ` Paul E. McKenney
2019-02-23 6:34 ` [PATCH v2 6/6] sched: Annotate perf_domain pointer " Joel Fernandes (Google)
2019-02-25 21:12 ` Paul E. McKenney
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