From: santosh.shilimkar@oracle.com
To: Amol Grover <frextrite@gmail.com>,
Santosh Shilimkar <ssantosh@kernel.org>,
Olof Johansson <olof@lixom.net>
Cc: arm@kernel.org, soc@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Joel Fernandes <joel@joelfernandes.org>,
Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH v2] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
Date: Sat, 18 Jan 2020 10:06:30 -0800 [thread overview]
Message-ID: <c58b6751-7502-fad4-e087-9f0bb744ebb9@oracle.com> (raw)
In-Reply-To: <20200118042433.4968-1-frextrite@gmail.com>
On 1/17/20 8:24 PM, Amol Grover wrote:
> inst->handles is traversed using list_for_each_entry_rcu
> outside an RCU read-side critical section but under the protection
> of knav_dev_lock.
>
> Hence, add corresponding lockdep expression to silence false-positive
> lockdep warnings, and harden RCU lists.
>
> Add macro for the corresponding lockdep expression.
>
> Signed-off-by: Amol Grover <frextrite@gmail.com>
> ---
> v2:
> - Remove rcu_read_lock_held() from lockdep expression since it is
> implicitly checked for.
>
Thanks.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
> drivers/soc/ti/knav_qmss_queue.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
> index 1ccc9064e1eb..37f3db6c041c 100644
> --- a/drivers/soc/ti/knav_qmss_queue.c
> +++ b/drivers/soc/ti/knav_qmss_queue.c
> @@ -25,6 +25,8 @@
>
> static struct knav_device *kdev;
> static DEFINE_MUTEX(knav_dev_lock);
> +#define knav_dev_lock_held() \
> + lockdep_is_held(&knav_dev_lock)
>
> /* Queue manager register indices in DTS */
> #define KNAV_QUEUE_PEEK_REG_INDEX 0
> @@ -52,8 +54,9 @@ static DEFINE_MUTEX(knav_dev_lock);
> #define knav_queue_idx_to_inst(kdev, idx) \
> (kdev->instances + (idx << kdev->inst_shift))
>
> -#define for_each_handle_rcu(qh, inst) \
> - list_for_each_entry_rcu(qh, &inst->handles, list)
> +#define for_each_handle_rcu(qh, inst) \
> + list_for_each_entry_rcu(qh, &inst->handles, list, \
> + knav_dev_lock_held())
>
> #define for_each_instance(idx, inst, kdev) \
> for (idx = 0, inst = kdev->instances; \
>
WARNING: multiple messages have this Message-ID (diff)
From: santosh.shilimkar@oracle.com
To: Amol Grover <frextrite@gmail.com>,
Santosh Shilimkar <ssantosh@kernel.org>,
Olof Johansson <olof@lixom.net>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org, soc@kernel.org, arm@kernel.org,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [Linux-kernel-mentees] [PATCH v2] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
Date: Sat, 18 Jan 2020 10:06:30 -0800 [thread overview]
Message-ID: <c58b6751-7502-fad4-e087-9f0bb744ebb9@oracle.com> (raw)
In-Reply-To: <20200118042433.4968-1-frextrite@gmail.com>
On 1/17/20 8:24 PM, Amol Grover wrote:
> inst->handles is traversed using list_for_each_entry_rcu
> outside an RCU read-side critical section but under the protection
> of knav_dev_lock.
>
> Hence, add corresponding lockdep expression to silence false-positive
> lockdep warnings, and harden RCU lists.
>
> Add macro for the corresponding lockdep expression.
>
> Signed-off-by: Amol Grover <frextrite@gmail.com>
> ---
> v2:
> - Remove rcu_read_lock_held() from lockdep expression since it is
> implicitly checked for.
>
Thanks.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
> drivers/soc/ti/knav_qmss_queue.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
> index 1ccc9064e1eb..37f3db6c041c 100644
> --- a/drivers/soc/ti/knav_qmss_queue.c
> +++ b/drivers/soc/ti/knav_qmss_queue.c
> @@ -25,6 +25,8 @@
>
> static struct knav_device *kdev;
> static DEFINE_MUTEX(knav_dev_lock);
> +#define knav_dev_lock_held() \
> + lockdep_is_held(&knav_dev_lock)
>
> /* Queue manager register indices in DTS */
> #define KNAV_QUEUE_PEEK_REG_INDEX 0
> @@ -52,8 +54,9 @@ static DEFINE_MUTEX(knav_dev_lock);
> #define knav_queue_idx_to_inst(kdev, idx) \
> (kdev->instances + (idx << kdev->inst_shift))
>
> -#define for_each_handle_rcu(qh, inst) \
> - list_for_each_entry_rcu(qh, &inst->handles, list)
> +#define for_each_handle_rcu(qh, inst) \
> + list_for_each_entry_rcu(qh, &inst->handles, list, \
> + knav_dev_lock_held())
>
> #define for_each_instance(idx, inst, kdev) \
> for (idx = 0, inst = kdev->instances; \
>
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
WARNING: multiple messages have this Message-ID (diff)
From: santosh.shilimkar@oracle.com
To: Amol Grover <frextrite@gmail.com>,
Santosh Shilimkar <ssantosh@kernel.org>,
Olof Johansson <olof@lixom.net>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org, soc@kernel.org, arm@kernel.org,
Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
Date: Sat, 18 Jan 2020 10:06:30 -0800 [thread overview]
Message-ID: <c58b6751-7502-fad4-e087-9f0bb744ebb9@oracle.com> (raw)
In-Reply-To: <20200118042433.4968-1-frextrite@gmail.com>
On 1/17/20 8:24 PM, Amol Grover wrote:
> inst->handles is traversed using list_for_each_entry_rcu
> outside an RCU read-side critical section but under the protection
> of knav_dev_lock.
>
> Hence, add corresponding lockdep expression to silence false-positive
> lockdep warnings, and harden RCU lists.
>
> Add macro for the corresponding lockdep expression.
>
> Signed-off-by: Amol Grover <frextrite@gmail.com>
> ---
> v2:
> - Remove rcu_read_lock_held() from lockdep expression since it is
> implicitly checked for.
>
Thanks.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
> drivers/soc/ti/knav_qmss_queue.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
> index 1ccc9064e1eb..37f3db6c041c 100644
> --- a/drivers/soc/ti/knav_qmss_queue.c
> +++ b/drivers/soc/ti/knav_qmss_queue.c
> @@ -25,6 +25,8 @@
>
> static struct knav_device *kdev;
> static DEFINE_MUTEX(knav_dev_lock);
> +#define knav_dev_lock_held() \
> + lockdep_is_held(&knav_dev_lock)
>
> /* Queue manager register indices in DTS */
> #define KNAV_QUEUE_PEEK_REG_INDEX 0
> @@ -52,8 +54,9 @@ static DEFINE_MUTEX(knav_dev_lock);
> #define knav_queue_idx_to_inst(kdev, idx) \
> (kdev->instances + (idx << kdev->inst_shift))
>
> -#define for_each_handle_rcu(qh, inst) \
> - list_for_each_entry_rcu(qh, &inst->handles, list)
> +#define for_each_handle_rcu(qh, inst) \
> + list_for_each_entry_rcu(qh, &inst->handles, list, \
> + knav_dev_lock_held())
>
> #define for_each_instance(idx, inst, kdev) \
> for (idx = 0, inst = kdev->instances; \
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-01-18 18:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-18 4:24 [PATCH v2] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists Amol Grover
2020-01-18 4:24 ` Amol Grover
2020-01-18 4:24 ` [Linux-kernel-mentees] " Amol Grover
2020-01-18 18:06 ` santosh.shilimkar [this message]
2020-01-18 18:06 ` santosh.shilimkar
2020-01-18 18:06 ` [Linux-kernel-mentees] " santosh.shilimkar
-- strict thread matches above, loose matches on Subject: below --
2020-01-17 13:30 Amol Grover
2020-01-17 13:30 ` Amol Grover
2020-01-17 18:24 ` santosh.shilimkar
2020-01-17 18:24 ` santosh.shilimkar
2020-01-17 19:25 ` Olof Johansson
2020-01-17 19:25 ` Olof Johansson
2020-01-18 4:07 ` Amol Grover
2020-01-18 4:07 ` Amol Grover
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