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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, James Smart <james.smart@broadcom.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 5.10 672/717] scsi: lpfc: Re-fix use after free in lpfc_rq_buf_free()
Date:   Mon, 28 Dec 2020 13:51:10 +0100
Message-Id: <20201228125053.178924484@linuxfoundation.org>
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From: James Smart <james.smart@broadcom.com>

commit e5785d3ec32f5f44dd88cd7b398e496742630469 upstream.

Commit 9816ef6ecbc1 ("scsi: lpfc: Use after free in lpfc_rq_buf_free()")
was made to correct a use after free condition in lpfc_rq_buf_free().
Unfortunately, a subsequent patch cut on a tree without the fix
inadvertently reverted the fix.

Put the fix back: Move the freeing of the rqb_entry to after the print
function that references it.

Link: https://lore.kernel.org/r/20201020202719.54726-4-james.smart@broadcom.com
Fixes: 411de511c694 ("scsi: lpfc: Fix RQ empty firmware trap")
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/lpfc/lpfc_mem.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/lpfc/lpfc_mem.c
+++ b/drivers/scsi/lpfc/lpfc_mem.c
@@ -721,7 +721,6 @@ lpfc_rq_buf_free(struct lpfc_hba *phba,
 	drqe.address_hi = putPaddrHigh(rqb_entry->dbuf.phys);
 	rc = lpfc_sli4_rq_put(rqb_entry->hrq, rqb_entry->drq, &hrqe, &drqe);
 	if (rc < 0) {
-		(rqbp->rqb_free_buffer)(phba, rqb_entry);
 		lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
 				"6409 Cannot post to HRQ %d: %x %x %x "
 				"DRQ %x %x\n",
@@ -731,6 +730,7 @@ lpfc_rq_buf_free(struct lpfc_hba *phba,
 				rqb_entry->hrq->entry_count,
 				rqb_entry->drq->host_index,
 				rqb_entry->drq->hba_index);
+		(rqbp->rqb_free_buffer)(phba, rqb_entry);
 	} else {
 		list_add_tail(&rqb_entry->hbuf.list, &rqbp->rqb_buffer_list);
 		rqbp->buffer_count++;