linux-kernel - [PATCH 4.4 012/135] scsi: lpfc: Fix lpfc_nodelist leak when processing unsolicited event

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Message-Id: <20200629155309.2495516-13-sashal@kernel.org>
Date:   Mon, 29 Jun 2020 11:51:06 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Xiyu Yang <xiyuyang19@...an.edu.cn>,
        Daniel Wagner <dwagner@...e.de>,
        James Smart <james.smart@...adcom.com>,
        Xin Tan <tanxin.ctf@...il.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.4 012/135] scsi: lpfc: Fix lpfc_nodelist leak when processing unsolicited event

From: Xiyu Yang <xiyuyang19@...an.edu.cn>

[ Upstream commit 7217e6e694da3aae6d17db8a7f7460c8d4817ebf ]

In order to create or activate a new node, lpfc_els_unsol_buffer() invokes
lpfc_nlp_init() or lpfc_enable_node() or lpfc_nlp_get(), all of them will
return a reference of the specified lpfc_nodelist object to "ndlp" with
increased refcnt.

When lpfc_els_unsol_buffer() returns, local variable "ndlp" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
lpfc_els_unsol_buffer(). When "ndlp" in DEV_LOSS, the function forgets to
decrease the refcnt increased by lpfc_nlp_init() or lpfc_enable_node() or
lpfc_nlp_get(), causing a refcnt leak.

Fix this issue by calling lpfc_nlp_put() when "ndlp" in DEV_LOSS.

Link: https://lore.kernel.org/r/1590416184-52592-1-git-send-email-xiyuyang19@fudan.edu.cn
Reviewed-by: Daniel Wagner <dwagner@...e.de>
Reviewed-by: James Smart <james.smart@...adcom.com>
Signed-off-by: Xiyu Yang <xiyuyang19@...an.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@...il.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/scsi/lpfc/lpfc_els.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 530b7df21322a..315dd25a0c44e 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -7315,6 +7315,8 @@ lpfc_els_unsol_buffer(struct lpfc_hba *phba, struct lpfc_sli_ring *pring,
 	spin_lock_irq(shost->host_lock);
 	if (ndlp->nlp_flag & NLP_IN_DEV_LOSS) {
 		spin_unlock_irq(shost->host_lock);
+		if (newnode)
+			lpfc_nlp_put(ndlp);
 		goto dropit;
 	}
 	spin_unlock_irq(shost->host_lock);
-- 
2.25.1