From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Justin Tee <justin.tee@broadcom.com>,
        James Smart <jsmart2021@gmail.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 261/323] scsi: lpfc: Fix list_add() corruption in lpfc_drain_txq()
Date:   Wed, 24 Nov 2021 12:57:31 +0100
Message-Id: <20211124115727.701496602@linuxfoundation.org>
In-Reply-To: <20211124115718.822024889@linuxfoundation.org>
References: <20211124115718.822024889@linuxfoundation.org>
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From: James Smart <jsmart2021@gmail.com>

[ Upstream commit 99154581b05c8fb22607afb7c3d66c1bace6aa5d ]

When parsing the txq list in lpfc_drain_txq(), the driver attempts to pass
the requests to the adapter. If such an attempt fails, a local "fail_msg"
string is set and a log message output.  The job is then added to a
completions list for cancellation.

Processing of any further jobs from the txq list continues, but since
"fail_msg" remains set, jobs are added to the completions list regardless
of whether a wqe was passed to the adapter.  If successfully added to
txcmplq, jobs are added to both lists resulting in list corruption.

Fix by clearing the fail_msg string after adding a job to the completions
list. This stops the subsequent jobs from being added to the completions
list unless they had an appropriate failure.

Link: https://lore.kernel.org/r/20210910233159.115896-2-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/lpfc/lpfc_sli.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 40d6537e64dd6..e72fc88aeb40e 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -19171,6 +19171,7 @@ lpfc_drain_txq(struct lpfc_hba *phba)
 					fail_msg,
 					piocbq->iotag, piocbq->sli4_xritag);
 			list_add_tail(&piocbq->list, &completions);
+			fail_msg = NULL;
 		}
 		spin_unlock_irqrestore(&pring->ring_lock, iflags);
 	}
-- 
2.33.0