From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maurizio Lombardi Date: Tue, 10 Nov 2020 21:29:33 +0000 Subject: Re: [PATCH 2/2] target: iscsi: fix a race condition when aborting a task Message-Id: <840cb2fe-5642-78d0-e700-d3652021cb5d@redhat.com> List-Id: References: <20201007145326.56850-1-mlombard@redhat.com> <20201007145326.56850-3-mlombard@redhat.com> <20daa17d-08e7-a412-4d33-bcf75587eca6@oracle.com> <1852a8bd-3edc-5c49-fa51-9afe52f125a8@redhat.com> <184667b1-032b-c36f-d1e7-5cfef961c763@oracle.com> <71691FED-C164-482C-B629-A8B89B81E566@oracle.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mike Christie , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, bvanassche@acm.org, m.lombardi85@gmail.com Dne 28. 10. 20 v 21:37 Mike Christie napsal(a): >> >> Possible solutions that I can think of: >> >> - Make iscsit_release_commands_from_conn() wait for the abort task to finish > > Yeah you could set a completion in there then have aborted_task do the complete() call maybe? > We could do something like this, what do you think? diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 067074ef50818..ffd3dbc53a42f 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -490,13 +490,16 @@ EXPORT_SYMBOL(iscsit_queue_rsp); void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd) { + struct se_cmd *se_cmd = cmd->se_cmd.se_tfo ? &cmd->se_cmd : NULL; + spin_lock_bh(&conn->cmd_lock); - if (!list_empty(&cmd->i_conn_node) && - !(cmd->se_cmd.transport_state & CMD_T_FABRIC_STOP)) + if (!list_empty(&cmd->i_conn_node)) list_del_init(&cmd->i_conn_node); spin_unlock_bh(&conn->cmd_lock); __iscsit_free_cmd(cmd, true); + if (se_cmd && se_cmd->abrt_task_compl) + complete(se_cmd->abrt_task_compl); } EXPORT_SYMBOL(iscsit_aborted_task); @@ -4080,6 +4083,7 @@ int iscsi_target_rx_thread(void *arg) static void iscsit_release_commands_from_conn(struct iscsi_conn *conn) { + DECLARE_COMPLETION_ONSTACK(compl); LIST_HEAD(tmp_list); struct iscsi_cmd *cmd = NULL, *cmd_tmp = NULL; struct iscsi_session *sess = conn->sess; @@ -4096,8 +4100,24 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn) if (se_cmd->se_tfo != NULL) { spin_lock_irq(&se_cmd->t_state_lock); + if (se_cmd->transport_state & CMD_T_ABORTED) { + /* + * LIO's abort path owns the cleanup for this, + * so put it back on the list and let + * aborted_task handle it. + */ + list_move_tail(&cmd->i_conn_node, &conn->conn_cmd_list); + WARN_ON_ONCE(se_cmd->abrt_task_compl); + se_cmd->abrt_task_compl = &compl; + } se_cmd->transport_state |= CMD_T_FABRIC_STOP; spin_unlock_irq(&se_cmd->t_state_lock); + + if (se_cmd->abrt_task_compl) { + spin_unlock_bh(&conn->cmd_lock); + wait_for_completion(&compl); + spin_lock_bh(&conn->cmd_lock); + } } } spin_unlock_bh(&conn->cmd_lock); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index db53a0d649da7..5611e6c00f18c 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1391,6 +1391,7 @@ void transport_init_se_cmd( init_completion(&cmd->t_transport_stop_comp); cmd->free_compl = NULL; cmd->abrt_compl = NULL; + cmd->abrt_task_compl = NULL; spin_lock_init(&cmd->t_state_lock); INIT_WORK(&cmd->work, NULL); kref_init(&cmd->cmd_kref); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 549947d407cfd..25cc451930281 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -491,6 +491,7 @@ struct se_cmd { struct list_head se_cmd_list; struct completion *free_compl; struct completion *abrt_compl; + struct completion *abrt_task_compl; const struct target_core_fabric_ops *se_tfo; sense_reason_t (*execute_cmd)(struct se_cmd *); sense_reason_t (*transport_complete_callback)(struct se_cmd *, bool, int *); -- 2.26.2