target: Fix double-free of se_cmd in target_complete_tmr_failure

Fabric drivers currently expect to internally release se_cmd in the event
of a TMR failure during target_submit_tmr(), which means the immediate call
to transport_generic_free_cmd() after TFO->queue_tm_rsp() from within
target_complete_tmr_failure() workqueue context is wrong.

This is done as some fabrics expect TMR operations to be acknowledged
before releasing the descriptor, so the assumption that core is releasing
se_cmd associated TMR memory is incorrect.  This fixes a OOPs where
transport_generic_free_cmd() was being called more than once.

This bug was originally observed with tcm_qla2xxx fabric ports.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index c33baff86aa699deacd04bd873e3c31fa5569cf5..9097155e9ebe7100c0bc1a4ac13b7c508a84ac8a 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1616,7 +1616,6 @@ static void target_complete_tmr_failure(struct work_struct *work)
 
        se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
        se_cmd->se_tfo->queue_tm_rsp(se_cmd);
-       transport_generic_free_cmd(se_cmd, 0);
 }
 
 /**