From: Joel Fernandes <joel@joelfernandes.org>
To: Amol Grover <frextrite@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH 2/2] events: callchain: Use RCU API to access RCU pointer
Date: Wed, 29 Jan 2020 17:19:09 -0500 [thread overview]
Message-ID: <20200129221909.GA74354@google.com> (raw)
In-Reply-To: <20200129160813.14263-2-frextrite@gmail.com>
On Wed, Jan 29, 2020 at 09:38:13PM +0530, Amol Grover wrote:
> callchain_cpus_entries is annotated as an RCU pointer.
> Hence rcu_dereference_protected or similar RCU API is
> required to dereference the pointer.
>
> This fixes the following sparse warning
> kernel/events/callchain.c:65:17: warning: incorrect type in assignment
>
> Signed-off-by: Amol Grover <frextrite@gmail.com>
> ---
> kernel/events/callchain.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
> index f91e1f41d25d..a672d02a1b3a 100644
> --- a/kernel/events/callchain.c
> +++ b/kernel/events/callchain.c
> @@ -62,7 +62,8 @@ static void release_callchain_buffers(void)
> {
> struct callchain_cpus_entries *entries;
>
> - entries = callchain_cpus_entries;
> + entries = rcu_dereference_protected(callchain_cpus_entries,
> + lockdep_is_held(&callchain_mutex));
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
thanks,
- Joel
> RCU_INIT_POINTER(callchain_cpus_entries, NULL);
> call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
> }
> --
> 2.24.1
>
next prev parent reply other threads:[~2020-01-29 22:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 16:08 [PATCH 1/2] events: callchain: Annotate RCU pointer with __rcu Amol Grover
2020-01-29 16:08 ` [PATCH 2/2] events: callchain: Use RCU API to access RCU pointer Amol Grover
2020-01-29 22:19 ` Joel Fernandes [this message]
2020-01-30 8:23 ` Peter Zijlstra
2020-01-30 10:14 ` Amol Grover
2020-01-30 13:32 ` Peter Zijlstra
2020-01-29 22:19 ` [PATCH 1/2] events: callchain: Annotate RCU pointer with __rcu Joel Fernandes
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