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authorNicholas Bellinger <nab@linux-iscsi.org>2017-10-27 22:19:26 -0800
committerNicholas Bellinger <nab@linux-iscsi.org>2017-11-07 19:50:24 -0800
commit1c21a48055a67ceb693e9c2587824a8de60a217c (patch)
tree43fd75f6f3cfc05510242b7d9a40fa9740b9b18a /include/target
parent9574a497df2bbc0a676b609ce0dd24d237cee3a6 (diff)
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target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK
This patch fixes bug where early se_cmd exceptions that occur before backend execution can result in use-after-free if/when a subsequent ABORT_TASK occurs for the same tag. Since an early se_cmd exception will have had se_cmd added to se_session->sess_cmd_list via target_get_sess_cmd(), it will not have CMD_T_COMPLETE set by the usual target_complete_cmd() backend completion path. This causes a subsequent ABORT_TASK + __target_check_io_state() to signal ABORT_TASK should proceed. As core_tmr_abort_task() executes, it will bring the outstanding se_cmd->cmd_kref count down to zero releasing se_cmd, after se_cmd has already been queued with error status into fabric driver response path code. To address this bug, introduce a CMD_T_PRE_EXECUTE bit that is set at target_get_sess_cmd() time, and cleared immediately before backend driver dispatch in target_execute_cmd() once CMD_T_ACTIVE is set. Then, check CMD_T_PRE_EXECUTE within __target_check_io_state() to determine when an early exception has occured, and avoid aborting this se_cmd since it will have already been queued into fabric driver response path code. Reported-by: Donald White <dew@datera.io> Cc: Donald White <dew@datera.io> Cc: Mike Christie <mchristi@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Cc: stable@vger.kernel.org # 3.14+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'include/target')
-rw-r--r--include/target/target_core_base.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index d3139a95ea77..ccf501b8359c 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -490,6 +490,7 @@ struct se_cmd {
#define CMD_T_STOP (1 << 5)
#define CMD_T_TAS (1 << 10)
#define CMD_T_FABRIC_STOP (1 << 11)
+#define CMD_T_PRE_EXECUTE (1 << 12)
spinlock_t t_state_lock;
struct kref cmd_kref;
struct completion t_transport_stop_comp;