[PATCH 1/1] lpfc: Early return after marking final NLP_DROPPED flag in dev_loss_tmo

From: Justin Tee <justintee8345@gmail.com>
To: linux-scsi@vger.kernel.org
Cc: jsmart2021@gmail.com, justin.tee@broadcom.com,
	Justin Tee <justintee8345@gmail.com>
Subject: [PATCH 1/1] lpfc: Early return after marking final NLP_DROPPED flag in dev_loss_tmo
Date: Fri,  8 Sep 2023 14:18:52 -0700	[thread overview]
Message-ID: <20230908211852.37576-1-justintee8345@gmail.com> (raw)

When a dev_loss_tmo event occurs, an ndlp lock is taken before checking
nlp_flag for NLP_DROPPED.  There is an attempt to restore the ndlp lock
when exiting the if statement, but the nlp_put kref could be the final
decrement causing a use-after-free memory access on a released ndlp object.

Instead of trying to reacquire the ndlp lock after checking nlp_flag, just
return after calling nlp_put.

Signed-off-by: Justin Tee <justin.tee@broadcom.com>
---
 drivers/scsi/lpfc/lpfc_hbadisc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index 51afb60859eb..674dd07aae72 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -203,7 +203,7 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 			ndlp->nlp_flag |= NLP_DROPPED;
 			spin_unlock_irqrestore(&ndlp->lock, iflags);
 			lpfc_nlp_put(ndlp);
-			spin_lock_irqsave(&ndlp->lock, iflags);
+			return;
 		}
 
 		spin_unlock_irqrestore(&ndlp->lock, iflags);
-- 
2.38.0

