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From:   Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To:     sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com,
        suganath-prabu.subramani@broadcom.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] scsi: Fix a use after free in pcie_device_make_active
Date:   Wed, 10 Mar 2021 22:19:48 -0800
Message-Id: <20210311061948.9348-1-lyl2019@mail.ustc.edu.cn>
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In pcie_device_make_active, it will drop the last reference
of pcie_device and release it by pcie_device_put(). It is
obviously that pcie_device_get() should be called before
release the pcie_device. Otherwise, it will cause a use after
free.

Fixes: d88e1eaba6eee ("scsi: mpt3sas: Add nvme device support in slave alloc, target alloc a…")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/scsi/mpt3sas/mpt3sas_scsih.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index ffca03064797..d39b5a1f496b 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -11433,11 +11433,11 @@ static void pcie_device_make_active(struct MPT3SAS_ADAPTER *ioc,
 
 	spin_lock_irqsave(&ioc->pcie_device_lock, flags);
 
+	pcie_device_get(pcie_device);
 	if (!list_empty(&pcie_device->list)) {
 		list_del_init(&pcie_device->list);
 		pcie_device_put(pcie_device);
 	}
-	pcie_device_get(pcie_device);
 	list_add_tail(&pcie_device->list, &ioc->pcie_device_list);
 
 	spin_unlock_irqrestore(&ioc->pcie_device_lock, flags);
-- 
2.25.1