On 11/10/20 3:29 PM, Maurizio Lombardi wrote:
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);
You can still hit your freed conn race I think. The aborted_task callout
is not the last time we are referencing the iscsi cmd and conn. That
code path still has to do the release_cmd callout for example. Once we
get past this wait_for_completion the abort code path could be still
running. If this iscsit_release_commands_from_conn completes first then
we can hit your case where we free the conn before the abort code path
has done release_cmd and we could hit that cmd->conn->sess reference.
I think if you do the complete in iscsit_release_cmd then we would not
hit that issue.
There might be a second issue though. What happens if aborted_task ran
first and deleted the cmd from the conn_cmd_list. It would then be
running while iscsit_release_commands_from_conn is running. We would
then not do the wait_for_completion above.
+ }
}
}
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;
This should be on the iscsi cmd since only iscsi uses it.
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 *);
