[PATCH 3.14 180/228] target: fix memory leak on XCOPY

Greg Kroah-Hartman
2014-06-04T23:23:02Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit 1e1110c43b1cda9fe77fc4a04835e460550e6b3c upstream.

On each processed XCOPY command, two "kmalloc-512" memory objects are
leaked. These represent two allocations of struct xcopy_pt_cmd in
target_core_xcopy.c.

The reason for the memory leak is that the cmd_kref field is not
initialized (thus, it is zero because the allocations were done with
kzalloc). When we decrement zero kref in target_put_sess_cmd, the result
is not zero, thus target_release_cmd_kref is not called.

This patch fixes the bug by moving kref initialization from
target_get_sess_cmd to transport_init_se_cmd (this function is called from
target_core_xcopy.c, so it will correctly initialize cmd_kref). It can be
easily verified that all code that calls target_get_sess_cmd also calls
transport_init_se_cmd earlier, thus moving kref_init shouldn't introduce
any new problems.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/target/target_core_transport.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1102,6 +1102,7 @@ void transport_init_se_cmd(
init_completion(&cmd->cmd_wait_comp);
init_completion(&cmd->task_stop_comp);
spin_lock_init(&cmd->t_state_lock);
+ kref_init(&cmd->cmd_kref);
cmd->transport_state = CMD_T_DEV_ACTIVE;

cmd->se_tfo = tfo;
@@ -2292,7 +2293,6 @@ int target_get_sess_cmd(struct se_sessio
unsigned long flags;
int ret = 0;

- kref_init(&se_cmd->cmd_kref);
/*
* Add a second kref if the fabric caller is expecting to handle
* fabric acknowledgement that requires two target_put_sess_cmd()