diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2017-03-23 17:19:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-21 09:31:20 +0200 |
| commit | 0ae3c95e3a31958bfb44bffe0beed12663700ba5 (patch) | |
| tree | ea700d2715678dadcdf52a5671dca7f046b8ffaf | |
| parent | eff58f9084a099fd7afe54b0bdcb68d4fbdbdd89 (diff) | |
iscsi-target: Fix TMR reference leak during session shutdown
commit efb2ea770bb3b0f40007530bc8b0c22f36e1c5eb upstream.
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>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/target/iscsi/iscsi_target_util.c | 12 |
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 1f38177207e0..da5a5fcb8c29 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -735,21 +735,23 @@ 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; |