[PATCH 5.11 226/342] scsi: lpfc: Fix reference counting errors in lpfc_cmpl_els_rsp()

From: Greg Kroah-Hartman
Date: Mon May 10 2021 - 07:48:15 EST


From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit f866eb06c087125619457b53e9211a9e758f64f7 ]

Call traces are being seen that result from a nodelist structure ref
counting error. They are typically seen after transmission of an LS_RJT ELS
response.

Aged code in lpfc_cmpl_els_rsp() calls lpfc_nlp_not_used() which, if the
ndlp reference count is exactly 1, will decrement the reference count.
Previously lpfc_nlp_put() was within lpfc_els_free_iocb(), and the 'put'
within the free would only be invoked if cmdiocb->context1 was not NULL.
Since the nodelist structure reference count is decremented when exiting
lpfc_cmpl_els_rsp() the lpfc_nlp_not_used() calls are no longer required.
Calling them is causing the reference count issue.

Fix by removing the lpfc_nlp_not_used() calls.

Link: https://lore.kernel.org/r/20210412013127.2387-4-jsmart2021@xxxxxxxxx
Co-developed-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/scsi/lpfc/lpfc_els.c | 64 +-----------------------------------
1 file changed, 1 insertion(+), 63 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 69e8a127b44f..2dce17827504 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -4465,10 +4465,7 @@ lpfc_mbx_cmpl_dflt_rpi(struct lpfc_hba *phba, LPFC_MBOXQ_t *pmb)
* nlp_flag bitmap in the ndlp data structure, if the mbox command reference
* field in the command IOCB is not NULL, the referred mailbox command will
* be send out, and then invokes the lpfc_els_free_iocb() routine to release
- * the IOCB. Under error conditions, such as when a LS_RJT is returned or a
- * link down event occurred during the discovery, the lpfc_nlp_not_used()
- * routine shall be invoked trying to release the ndlp if no other threads
- * are currently referring it.
+ * the IOCB.
**/
static void
lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
@@ -4478,10 +4475,8 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
struct lpfc_vport *vport = ndlp ? ndlp->vport : NULL;
struct Scsi_Host *shost = vport ? lpfc_shost_from_vport(vport) : NULL;
IOCB_t *irsp;
- uint8_t *pcmd;
LPFC_MBOXQ_t *mbox = NULL;
struct lpfc_dmabuf *mp = NULL;
- uint32_t ls_rjt = 0;

irsp = &rspiocb->iocb;

@@ -4493,18 +4488,6 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
if (cmdiocb->context_un.mbox)
mbox = cmdiocb->context_un.mbox;

- /* First determine if this is a LS_RJT cmpl. Note, this callback
- * function can have cmdiocb->contest1 (ndlp) field set to NULL.
- */
- pcmd = (uint8_t *) (((struct lpfc_dmabuf *) cmdiocb->context2)->virt);
- if (ndlp && (*((uint32_t *) (pcmd)) == ELS_CMD_LS_RJT)) {
- /* A LS_RJT associated with Default RPI cleanup has its own
- * separate code path.
- */
- if (!(ndlp->nlp_flag & NLP_RM_DFLT_RPI))
- ls_rjt = 1;
- }
-
/* Check to see if link went down during discovery */
if (!ndlp || lpfc_els_chk_latt(vport)) {
if (mbox) {
@@ -4515,15 +4498,6 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
}
mempool_free(mbox, phba->mbox_mem_pool);
}
- if (ndlp && (ndlp->nlp_flag & NLP_RM_DFLT_RPI))
- if (lpfc_nlp_not_used(ndlp)) {
- ndlp = NULL;
- /* Indicate the node has already released,
- * should not reference to it from within
- * the routine lpfc_els_free_iocb.
- */
- cmdiocb->context1 = NULL;
- }
goto out;
}

@@ -4601,29 +4575,6 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
"Data: x%x x%x x%x\n",
ndlp->nlp_DID, ndlp->nlp_flag, ndlp->nlp_state,
ndlp->nlp_rpi);
-
- if (lpfc_nlp_not_used(ndlp)) {
- ndlp = NULL;
- /* Indicate node has already been released,
- * should not reference to it from within
- * the routine lpfc_els_free_iocb.
- */
- cmdiocb->context1 = NULL;
- }
- } else {
- /* Do not drop node for lpfc_els_abort'ed ELS cmds */
- if (!lpfc_error_lost_link(irsp) &&
- ndlp->nlp_flag & NLP_ACC_REGLOGIN) {
- if (lpfc_nlp_not_used(ndlp)) {
- ndlp = NULL;
- /* Indicate node has already been
- * released, should not reference
- * to it from within the routine
- * lpfc_els_free_iocb.
- */
- cmdiocb->context1 = NULL;
- }
- }
}
mp = (struct lpfc_dmabuf *)mbox->ctx_buf;
if (mp) {
@@ -4639,19 +4590,6 @@ out:
ndlp->nlp_flag &= ~NLP_ACC_REGLOGIN;
ndlp->nlp_flag &= ~NLP_RM_DFLT_RPI;
spin_unlock_irq(&ndlp->lock);
-
- /* If the node is not being used by another discovery thread,
- * and we are sending a reject, we are done with it.
- * Release driver reference count here and free associated
- * resources.
- */
- if (ls_rjt)
- if (lpfc_nlp_not_used(ndlp))
- /* Indicate node has already been released,
- * should not reference to it from within
- * the routine lpfc_els_free_iocb.
- */
- cmdiocb->context1 = NULL;
}

/* Release the originating I/O reference. */
--
2.30.2