From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Date: Tue, 02 Apr 2019 19:58:05 +0000 Subject: [PATCH 01/11] target/core: Fix a race condition in the LUN lookup code Message-Id: <20190402195815.254796-2-bvanassche@acm.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: target-devel@vger.kernel.org The rcu_dereference(deve->se_lun) expression occurs two times in the LUN lookup functions. Since these expressions are not serialized against deve->se_lun assignments each of these expressions may yield a different result. Avoid that the wrong LUN pointer is stored in se_cmd by reading deve->se_lun only once. Cc: Mike Christie Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Nicholas Bellinger Fixes: 29a05deebf6c ("target: Convert se_node_acl->device_list[] to RCU hlist") # v4.10 Signed-off-by: Bart Van Assche --- drivers/target/target_core_device.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 1f8482b6473b..7eae1c823c4e 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -85,7 +85,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u64 unpacked_lun) goto out_unlock; } - se_cmd->se_lun = rcu_dereference(deve->se_lun); + se_cmd->se_lun = se_lun; se_cmd->pr_res_key = deve->pr_res_key; se_cmd->orig_fe_lun = unpacked_lun; se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD; @@ -176,7 +176,7 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u64 unpacked_lun) goto out_unlock; } - se_cmd->se_lun = rcu_dereference(deve->se_lun); + se_cmd->se_lun = se_lun; se_cmd->pr_res_key = deve->pr_res_key; se_cmd->orig_fe_lun = unpacked_lun; se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD; -- 2.21.0.196.g041f5ea1cf98