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commit 1c21a48055a67ceb693e9c2587824a8de60a217c upstream. 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> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.