[PATCH 3.12 90/98] target: Fix target_release_cmd_kref shutdown comp leak

From: Jiri Slaby
Date: Mon Apr 11 2016 - 09:31:09 EST


From: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 5e47f1985d7107331c3f64fb3ec83d66fd73577e upstream.

This patch fixes an active I/O shutdown bug for fabric
drivers using target_wait_for_sess_cmds(), where se_cmd
descriptor shutdown would result in hung tasks waiting
indefinitely for se_cmd->cmd_wait_comp to complete().

To address this bug, drop the incorrect list_del_init()
usage in target_wait_for_sess_cmds() and always complete()
during se_cmd target_release_cmd_kref() put, in order to
let caller invoke the final fabric release callback
into se_cmd->se_tfo->release_cmd() code.

[3.12 backport: we have only list_del]

Reported-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Tested-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Signed-off-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/target/target_core_transport.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index b335709f050f..9291eaa09046 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2438,8 +2438,6 @@ void target_wait_for_sess_cmds(struct se_session *se_sess)

list_for_each_entry_safe(se_cmd, tmp_cmd,
&se_sess->sess_wait_list, se_cmd_list) {
- list_del(&se_cmd->se_cmd_list);
-
pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
" %d\n", se_cmd, se_cmd->t_state,
se_cmd->se_tfo->get_cmd_state(se_cmd));
--
2.8.1