Code: static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
				 struct srpt_recv_ioctx *recv_ioctx,
				 struct srpt_send_ioctx *send_ioctx)
{
	struct srp_tsk_mgmt *srp_tsk;
 	struct se_cmd *cmd;
 	struct se_session *sess = ch->sess;
 	uint64_t unpacked_lun;
	uint32_t tag = 0;
 	int tcm_tmr;
 	int rc;
 
	BUG_ON(!send_ioctx);

	srp_tsk = recv_ioctx->ioctx.buf;
	cmd = &send_ioctx->cmd;

	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);

 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
 	send_ioctx->cmd.tag = srp_tsk->tag;
 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
	if (tcm_tmr < 0) {
		send_ioctx->cmd.se_tmr_req->response =
			TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
		goto fail;
	}
 	unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_tsk->lun,
 				       sizeof(srp_tsk->lun));
	if (srp_tsk->tsk_mgmt_func == SRP_TSK_ABORT_TASK) {
		rc = srpt_rx_mgmt_fn_tag(send_ioctx, srp_tsk->task_tag);
		if (rc < 0) {
			send_ioctx->cmd.se_tmr_req->response =
					TMR_TASK_DOES_NOT_EXIST;
			goto fail;
		}
		tag = srp_tsk->task_tag;
	}
 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL, unpacked_lun,
				srp_tsk, tcm_tmr, GFP_KERNEL, tag,
 				TARGET_SCF_ACK_KREF);
 	if (rc != 0) {
 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
		goto fail;
	}
	return;
fail:
	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
}

Commit Message: IB/srpt: Simplify srpt_handle_tsk_mgmt()

Let the target core check task existence instead of the SRP target
driver. Additionally, let the target core check the validity of the
task management request instead of the ib_srpt driver.

This patch fixes the following kernel crash:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
IP: [<ffffffffa0565f37>] srpt_handle_new_iu+0x6d7/0x790 [ib_srpt]
Oops: 0002 [#1] SMP
Call Trace:
 [<ffffffffa05660ce>] srpt_process_completion+0xde/0x570 [ib_srpt]
 [<ffffffffa056669f>] srpt_compl_thread+0x13f/0x160 [ib_srpt]
 [<ffffffff8109726f>] kthread+0xcf/0xe0
 [<ffffffff81613cfc>] ret_from_fork+0x7c/0xb0

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Fixes: 3e4f574857ee ("ib_srpt: Convert TMR path to target_submit_tmr")
Tested-by: Alex Estrin <alex.estrin@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
CWE ID: CWE-476
static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
				 struct srpt_recv_ioctx *recv_ioctx,
				 struct srpt_send_ioctx *send_ioctx)
{
	struct srp_tsk_mgmt *srp_tsk;
 	struct se_cmd *cmd;
 	struct se_session *sess = ch->sess;
 	uint64_t unpacked_lun;
 	int tcm_tmr;
 	int rc;
 
	BUG_ON(!send_ioctx);

	srp_tsk = recv_ioctx->ioctx.buf;
	cmd = &send_ioctx->cmd;

	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);

 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
 	send_ioctx->cmd.tag = srp_tsk->tag;
 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
 	unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_tsk->lun,
 				       sizeof(srp_tsk->lun));
 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL, unpacked_lun,
				srp_tsk, tcm_tmr, GFP_KERNEL, srp_tsk->task_tag,
 				TARGET_SCF_ACK_KREF);
 	if (rc != 0) {
 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
		goto fail;
	}
	return;
fail:
	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
}
