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[89.177.130.96]) by smtp.gmail.com with ESMTPSA id x7sm12742129wrq.41.2020.02.23.03.01.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Feb 2020 03:01:46 -0800 (PST) Date: Sun, 23 Feb 2020 12:01:45 +0100 From: Jiri Pirko 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() Message-ID: <20200223110145.GE2228@nanopsycho> References: <20200223105253.30469-1-madhuparnabhowmik10@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200223105253.30469-1-madhuparnabhowmik10@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sun, Feb 23, 2020 at 11:52:53AM CET, madhuparnabhowmik10@gmail.com wrote: >From: Madhuparna Bhowmik > >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 >--- > 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 >