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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: Kai.Makisara@kolumbus.fi, 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 st_open
Date: Wed, 10 Mar 2021 22:46:36 -0800
Message-ID: <20210311064636.10522-1-lyl2019@mail.ustc.edu.cn> (raw)

In st_open, if STp->in_use is true, STp will be freed by
scsi_tape_put(). However, STp is still used by DEBC_printk()
after. It is better to DEBC_printk() before scsi_tape_put().

Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/scsi/st.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 841ad2fc369a..9ca536aae784 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -1269,8 +1269,8 @@ static int st_open(struct inode *inode, struct file *filp)
 	spin_lock(&st_use_lock);
 	if (STp->in_use) {
 		spin_unlock(&st_use_lock);
-		scsi_tape_put(STp);
 		DEBC_printk(STp, "Device already in use.\n");
+		scsi_tape_put(STp);
 		return (-EBUSY);
 	}
 
-- 
2.25.1



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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11  6:46 Lv Yunlong [this message]
2021-03-11 18:10 ` "Kai Mäkisara (Kolumbus)"
2021-03-16  3:13 ` Martin K. Petersen

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