target_sess_cmd_list_waiting() might hit on a condition where
the kref for the command is already 0, but the destructor has
not been called yet (or is stuck in waiting for a spin lock).
Rather than leaving the command on the list we should explicitly
remove it to avoid race issues later on.
Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
---
drivers/target/target_core_transport.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 2e1a6d8..ce136f0 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2547,8 +2547,8 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
* fabric acknowledgement that requires two target_put_sess_cmd()
* invocations before se_cmd descriptor release.
*/
- if (ack_kref)
- kref_get(&se_cmd->cmd_kref);
+ if (ack_kref && !kref_get_unless_zero(&se_cmd->cmd_kref))
+ return -EINVAL;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
if (se_sess->sess_tearing_down) {
@@ -2627,7 +2627,7 @@ EXPORT_SYMBOL(target_put_sess_cmd);
*/
void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
{
- struct se_cmd *se_cmd;
+ struct se_cmd *se_cmd, *tmp_cmd;
unsigned long flags;
int rc;
@@ -2639,7 +2639,8 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
se_sess->sess_tearing_down = 1;
list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
- list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) {
+ list_for_each_entry_safe(se_cmd, tmp_cmd,
+ &se_sess->sess_wait_list, se_cmd_list) {
rc = kref_get_unless_zero(&se_cmd->cmd_kref);
if (rc) {
spin_lock(&se_cmd->t_state_lock);
@@ -2648,7 +2649,8 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
se_cmd->transport_state |= CMD_T_FABRIC_STOP;
}
spin_unlock(&se_cmd->t_state_lock);
- }
+ } else
+ list_del_init(&se_cmd->se_cmd_list);
}
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
--
1.8.5.6
--
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