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Commit ee2a02a6 authored by Ewan D. Milne's avatar Ewan D. Milne Committed by Greg Kroah-Hartman
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scsi: lpfc: nvmet: avoid hang / use-after-free when destroying targetport 



[ Upstream commit c41f59884be5cca293ed61f3d64637dbba3a6381 ]

We cannot wait on a completion object in the lpfc_nvme_targetport structure
in the _destroy_targetport() code path because the NVMe/fc transport will
free that structure immediately after the .targetport_delete() callback.
This results in a use-after-free, and a hang if slub_debug=FZPU is enabled.

Fix this by putting the completion on the stack.

Signed-off-by: default avatarEwan D. Milne <emilne@redhat.com>
Acked-by: default avatarJames Smart <james.smart@broadcom.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 30b62656

drivers/scsi/lpfc/lpfc_nvmet.c

+5 −3
Original line number Diff line number Diff line
@@ -1003,7 +1003,8 @@ lpfc_nvmet_targetport_delete(struct nvmet_fc_target_port *targetport) 
	struct lpfc_nvmet_tgtport *tport = targetport->private;



	/* release any threads waiting for the unreg to complete */

	complete(&tport->tport_unreg_done);

	if (tport->phba->targetport)

		complete(tport->tport_unreg_cmp);

}



static void
@@ -1700,6 +1701,7 @@ lpfc_nvmet_destroy_targetport(struct lpfc_hba *phba) 
	struct lpfc_nvmet_tgtport *tgtp;

	struct lpfc_queue *wq;

	uint32_t qidx;

	DECLARE_COMPLETION_ONSTACK(tport_unreg_cmp);



	if (phba->nvmet_support == 0)

		return;
@@ -1709,9 +1711,9 @@ lpfc_nvmet_destroy_targetport(struct lpfc_hba *phba) 
			wq = phba->sli4_hba.nvme_wq[qidx];

			lpfc_nvmet_wqfull_flush(phba, wq, NULL);

		}

		init_completion(&tgtp->tport_unreg_done);

		tgtp->tport_unreg_cmp = &tport_unreg_cmp;

		nvmet_fc_unregister_targetport(phba->targetport);

		wait_for_completion_timeout(&tgtp->tport_unreg_done, 5);

		wait_for_completion_timeout(&tport_unreg_cmp, 5);

		lpfc_nvmet_cleanup_io_context(phba);

	}

	phba->targetport = NULL;

drivers/scsi/lpfc/lpfc_nvmet.h

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ 
/* Used for NVME Target */

struct lpfc_nvmet_tgtport {

	struct lpfc_hba *phba;

	struct completion tport_unreg_done;

	struct completion *tport_unreg_cmp;



	/* Stats counters - lpfc_nvmet_unsol_ls_buffer */

	atomic_t rcv_ls_req_in;