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 3/6] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu
Date: Mon, 25 Feb 2019 13:10:26 -0800 [thread overview]
Message-ID: <20190225211026.GX4072@linux.ibm.com> (raw)
In-Reply-To: <20190223063434.6793-4-joel@joelfernandes.org>
On Sat, Feb 23, 2019 at 01:34:31AM -0500, Joel Fernandes (Google) wrote:
> Recently I added an RCU annotation check to rcu_assign_pointer(). All
> pointers assigned to RCU protected data are to be annotated with __rcu
> inorder to be able to use rcu_assign_pointer() similar to checks in
> other RCU APIs.
>
> This resulted in a sparse error: kernel//sched/cpufreq.c:41:9: sparse:
> error: incompatible types in comparison expression (different address
> spaces)
>
> Fix this by annotating cpufreq_update_util_data pointer with __rcu. This
> will also help sparse catch any future RCU misuage bugs.
>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
>From an RCU perspective:
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
> ---
> kernel/sched/cpufreq.c | 2 +-
> kernel/sched/sched.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
> index 22bd8980f32f..e316ee7bb2e5 100644
> --- a/kernel/sched/cpufreq.c
> +++ b/kernel/sched/cpufreq.c
> @@ -7,7 +7,7 @@
> */
> #include "sched.h"
>
> -DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
> +DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
>
> /**
> * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index d04530bf251f..2ab545d40381 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -2166,7 +2166,7 @@ static inline u64 irq_time_read(int cpu)
> #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
>
> #ifdef CONFIG_CPU_FREQ
> -DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
> +DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
>
> /**
> * cpufreq_update_util - Take a note about CPU utilization changes.
> --
> 2.21.0.rc0.258.g878e2cd30e-goog
>
next prev parent reply other threads:[~2019-02-25 21:10 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
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 [this message]
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
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=20190225211026.GX4072@linux.ibm.com \
--to=paulmck@linux.ibm.com \
--cc=ast@kernel.org \
--cc=christian@brauner.io \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=dsahern@gmail.com \
--cc=hawk@kernel.org \
--cc=jakub.kicinski@netronome.com \
--cc=jeffrey.t.kirsher@intel.com \
--cc=jiangshanlai@gmail.com \
--cc=joel@joelfernandes.org \
--cc=john.fastabend@gmail.com \
--cc=josh@joshtriplett.org \
--cc=kafai@fb.com \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=kernel-team@android.com \
--cc=ktkhai@virtuozzo.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=quentin.perret@arm.com \
--cc=rcu@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=songliubraving@fb.com \
--cc=vincent.guittot@linaro.org \
--cc=xdp-newbies@vger.kernel.org \
--cc=yhs@fb.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;
as well as URLs for NNTP newsgroup(s).