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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+4496e82090657320efc6@syzkaller.appspotmail.com,
        Qiujun Huang <hqjagain@gmail.com>,
        Hillf Danton <hdanton@sina.com>,
        Marcel Holtmann <marcel@holtmann.org>
Subject: [PATCH 4.4 26/29] Bluetooth: RFCOMM: fix ODEBUG bug in rfcomm_dev_ioctl
Date:   Sat, 11 Apr 2020 14:08:56 +0200
Message-Id: <20200411115412.206046292@linuxfoundation.org>
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From: Qiujun Huang <hqjagain@gmail.com>

commit 71811cac8532b2387b3414f7cd8fe9e497482864 upstream.

Needn't call 'rfcomm_dlc_put' here, because 'rfcomm_dlc_exists' didn't
increase dlc->refcnt.

Reported-by: syzbot+4496e82090657320efc6@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Suggested-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/bluetooth/rfcomm/tty.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -413,10 +413,8 @@ static int __rfcomm_create_dev(struct so
 		dlc = rfcomm_dlc_exists(&req.src, &req.dst, req.channel);
 		if (IS_ERR(dlc))
 			return PTR_ERR(dlc);
-		else if (dlc) {
-			rfcomm_dlc_put(dlc);
+		if (dlc)
 			return -EBUSY;
-		}
 		dlc = rfcomm_dlc_alloc(GFP_KERNEL);
 		if (!dlc)
 			return -ENOMEM;