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From: Jiri Pirko <jiri@resnulli.us>
To: madhuparnabhowmik10@gmail.com
Cc: paulmck@kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, jiri@mellanox.com,
	joel@joelfernandes.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	davem@davemloft.net
Subject: Re: [Linux-kernel-mentees] [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()
Date: Sun, 23 Feb 2020 12:01:45 +0100	[thread overview]
Message-ID: <20200223110145.GE2228@nanopsycho> (raw)
In-Reply-To: <20200223105253.30469-1-madhuparnabhowmik10@gmail.com>

Sun, Feb 23, 2020 at 11:52:53AM CET, madhuparnabhowmik10@gmail.com wrote:
>From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
>devlink_dpipe_table_find() should be called under either
>rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
>calls devlink_dpipe_table_find() without holding the lock
>and acquires it later. Therefore hold the devlink->lock
>from the beginning of devlink_dpipe_table_register().
>
>Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>---
> net/core/devlink.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 4c63c9a4c09e..61a350f59741 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -6838,26 +6838,35 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> 				 void *priv, bool counter_control_extern)
> {
> 	struct devlink_dpipe_table *table;
>+	int err = 0;
> 
>-	if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
>-		return -EEXIST;
>+	mutex_lock(&devlink->lock);
> 
>-	if (WARN_ON(!table_ops->size_get))
>-		return -EINVAL;
>+	if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
>+		err = -EEXIST;
>+		goto unlock;
>+	}
>+
>+	if (WARN_ON(!table_ops->size_get)) {
>+		err = -EINVAL;
>+		goto unlock;
>+	}


Put this check out of the lock please.


> 
> 	table = kzalloc(sizeof(*table), GFP_KERNEL);
>-	if (!table)
>-		return -ENOMEM;
>+	if (!table) {
>+		err = -ENOMEM;
>+		goto unlock;
>+	}
> 
> 	table->name = table_name;
> 	table->table_ops = table_ops;
> 	table->priv = priv;
> 	table->counter_control_extern = counter_control_extern;
> 
>-	mutex_lock(&devlink->lock);
> 	list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
>+unlock:
> 	mutex_unlock(&devlink->lock);
>-	return 0;
>+	return err;
> }
> EXPORT_SYMBOL_GPL(devlink_dpipe_table_register);
> 
>-- 
>2.17.1
>
_______________________________________________
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: Jiri Pirko <jiri@resnulli.us>
To: madhuparnabhowmik10@gmail.com
Cc: jiri@mellanox.com, davem@davemloft.net, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, joel@joelfernandes.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	paulmck@kernel.org
Subject: Re: [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()
Date: Sun, 23 Feb 2020 12:01:45 +0100	[thread overview]
Message-ID: <20200223110145.GE2228@nanopsycho> (raw)
In-Reply-To: <20200223105253.30469-1-madhuparnabhowmik10@gmail.com>

Sun, Feb 23, 2020 at 11:52:53AM CET, madhuparnabhowmik10@gmail.com wrote:
>From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
>devlink_dpipe_table_find() should be called under either
>rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
>calls devlink_dpipe_table_find() without holding the lock
>and acquires it later. Therefore hold the devlink->lock
>from the beginning of devlink_dpipe_table_register().
>
>Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>---
> net/core/devlink.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 4c63c9a4c09e..61a350f59741 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -6838,26 +6838,35 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> 				 void *priv, bool counter_control_extern)
> {
> 	struct devlink_dpipe_table *table;
>+	int err = 0;
> 
>-	if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
>-		return -EEXIST;
>+	mutex_lock(&devlink->lock);
> 
>-	if (WARN_ON(!table_ops->size_get))
>-		return -EINVAL;
>+	if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
>+		err = -EEXIST;
>+		goto unlock;
>+	}
>+
>+	if (WARN_ON(!table_ops->size_get)) {
>+		err = -EINVAL;
>+		goto unlock;
>+	}


Put this check out of the lock please.


> 
> 	table = kzalloc(sizeof(*table), GFP_KERNEL);
>-	if (!table)
>-		return -ENOMEM;
>+	if (!table) {
>+		err = -ENOMEM;
>+		goto unlock;
>+	}
> 
> 	table->name = table_name;
> 	table->table_ops = table_ops;
> 	table->priv = priv;
> 	table->counter_control_extern = counter_control_extern;
> 
>-	mutex_lock(&devlink->lock);
> 	list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
>+unlock:
> 	mutex_unlock(&devlink->lock);
>-	return 0;
>+	return err;
> }
> EXPORT_SYMBOL_GPL(devlink_dpipe_table_register);
> 
>-- 
>2.17.1
>

  reply	other threads:[~2020-02-23 11:01 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-23 10:52 [Linux-kernel-mentees] [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register() madhuparnabhowmik10
2020-02-23 10:52 ` madhuparnabhowmik10
2020-02-23 11:01 ` Jiri Pirko [this message]
2020-02-23 11:01   ` Jiri Pirko
  -- strict thread matches above, loose matches on Subject: below --
2020-02-23 11:22 [Linux-kernel-mentees] " madhuparnabhowmik10
2020-02-23 18:17 ` Jiri Pirko
2020-02-22  6:52 madhuparnabhowmik10
2020-02-23  6:43 ` Jiri Pirko
2020-02-23 10:56   ` Madhuparna Bhowmik
2020-02-21 18:09 madhuparnabhowmik10
2020-02-22  6:26 ` Jiri Pirko
2020-02-22  6:55   ` Madhuparna Bhowmik

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