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authorNicholas Bellinger <nab@linux-iscsi.org>2017-03-23 17:19:24 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2017-03-30 01:36:51 -0700
commitefb2ea770bb3b0f40007530bc8b0c22f36e1c5eb (patch)
tree503c3d80c8872dbf3a1f05bb767c2054c9a65573 /drivers/target/iscsi
parentafea03fcf3d5db8a968f4b97797b8b83ada0dba3 (diff)
iscsi-target: Fix TMR reference leak during session shutdown
This patch fixes a iscsi-target specific TMR reference leak during session shutdown, that could occur when a TMR was quiesced before the hand-off back to iscsi-target code via transport_cmd_check_stop_to_fabric(). The reference leak happens because iscsit_free_cmd() was incorrectly skipping the final target_put_sess_cmd() for TMRs when transport_generic_free_cmd() returned zero because the se_cmd->cmd_kref did not reach zero, due to the missing se_cmd assignment in original code. The result was iscsi_cmd and it's associated se_cmd memory would be freed once se_sess->sess_cmd_map where released, but the associated se_tmr_req was leaked and remained part of se_device->dev_tmr_list. This bug would manfiest itself as kernel paging request OOPsen in core_tmr_lun_reset(), when a left-over se_tmr_req attempted to dereference it's se_cmd pointer that had already been released during normal session shutdown. To address this bug, go ahead and treat ISCSI_OP_SCSI_CMD and ISCSI_OP_SCSI_TMFUNC the same when there is an extra se_cmd->cmd_kref to drop in iscsit_free_cmd(), and use op_scsi to signal __iscsit_free_cmd() when the former needs to clear any further iscsi related I/O state. Reported-by: Rob Millner <rlm@daterainc.com> Cc: Rob Millner <rlm@daterainc.com> Reported-by: Chu Yuan Lin <cyl@datera.io> Cc: Chu Yuan Lin <cyl@datera.io> Tested-by: Chu Yuan Lin <cyl@datera.io> Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/iscsi')
-rw-r--r--drivers/target/iscsi/iscsi_target_util.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 5041a9c8bdcb..b4640338f8d8 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -737,21 +737,23 @@ void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
{
struct se_cmd *se_cmd = NULL;
int rc;
+ bool op_scsi = false;
/*
* Determine if a struct se_cmd is associated with
* this struct iscsi_cmd.
*/
switch (cmd->iscsi_opcode) {
case ISCSI_OP_SCSI_CMD:
- se_cmd = &cmd->se_cmd;
- __iscsit_free_cmd(cmd, true, shutdown);
+ op_scsi = true;
/*
* Fallthrough
*/
case ISCSI_OP_SCSI_TMFUNC:
- rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
- if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
- __iscsit_free_cmd(cmd, true, shutdown);
+ se_cmd = &cmd->se_cmd;
+ __iscsit_free_cmd(cmd, op_scsi, shutdown);
+ rc = transport_generic_free_cmd(se_cmd, shutdown);
+ if (!rc && shutdown && se_cmd->se_sess) {
+ __iscsit_free_cmd(cmd, op_scsi, shutdown);
target_put_sess_cmd(se_cmd);
}
break;