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H A D | iscsi_target.c | f3619935 Fri Nov 13 19:46:18 CST 2020 Mike Christie <michael.christie@oracle.com> scsi: target: iscsi: Fix cmd abort fabric stop race
Maurizio found a race where the abort and cmd stop paths can race as follows:
1. thread1 runs iscsit_release_commands_from_conn and sets CMD_T_FABRIC_STOP.
2. thread2 runs iscsit_aborted_task and then does __iscsit_free_cmd. It then returns from the aborted_task callout and we finish target_handle_abort and do:
target_handle_abort -> transport_cmd_check_stop_to_fabric -> lio_check_stop_free -> target_put_sess_cmd
The cmd is now freed.
3. thread1 now finishes iscsit_release_commands_from_conn and runs iscsit_free_cmd while accessing a command we just released.
In __target_check_io_state we check for CMD_T_FABRIC_STOP and set the CMD_T_ABORTED if the driver is not cleaning up the cmd because of a session shutdown. However, iscsit_release_commands_from_conn only sets the CMD_T_FABRIC_STOP and does not check to see if the abort path has claimed completion ownership of the command.
This adds a check in iscsit_release_commands_from_conn so only the abort or fabric stop path cleanup the command.
Link: https://lore.kernel.org/r/1605318378-9269-1-git-send-email-michael.christie@oracle.com Reported-by: Maurizio Lombardi <mlombard@redhat.com> Reviewed-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> f3619935 Fri Nov 13 19:46:18 CST 2020 Mike Christie <michael.christie@oracle.com> scsi: target: iscsi: Fix cmd abort fabric stop race Maurizio found a race where the abort and cmd stop paths can race as follows: 1. thread1 runs iscsit_release_commands_from_conn and sets CMD_T_FABRIC_STOP. 2. thread2 runs iscsit_aborted_task and then does __iscsit_free_cmd. It then returns from the aborted_task callout and we finish target_handle_abort and do: target_handle_abort -> transport_cmd_check_stop_to_fabric -> lio_check_stop_free -> target_put_sess_cmd The cmd is now freed. 3. thread1 now finishes iscsit_release_commands_from_conn and runs iscsit_free_cmd while accessing a command we just released. In __target_check_io_state we check for CMD_T_FABRIC_STOP and set the CMD_T_ABORTED if the driver is not cleaning up the cmd because of a session shutdown. However, iscsit_release_commands_from_conn only sets the CMD_T_FABRIC_STOP and does not check to see if the abort path has claimed completion ownership of the command. This adds a check in iscsit_release_commands_from_conn so only the abort or fabric stop path cleanup the command. Link: https://lore.kernel.org/r/1605318378-9269-1-git-send-email-michael.christie@oracle.com Reported-by: Maurizio Lombardi <mlombard@redhat.com> Reviewed-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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