Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Pavel Skripkin <paskripkin@gmail.com>
To:     brookebasile@gmail.com
Cc:     ath9k-devel@qca.qualcomm.com, davem@davemloft.net,
        gregkh@linuxfoundation.org, kuba@kernel.org, kvalo@codeaurora.org,
        linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        syzbot+89bd486af9427a9fc605@syzkaller.appspotmail.com,
        syzkaller-bugs@googlegroups.com
Subject: Memory leak in ath9k_hif_usb_dealloc_tx_urbs()
Date:   Tue, 30 Mar 2021 22:36:52 +0300
Message-Id: <20210330193652.10642-1-paskripkin@gmail.com>
In-Reply-To: <20200911071427.32354-1-brookebasile@gmail.com>
References: <20200911071427.32354-1-brookebasile@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi!

I did some debugging on this
https://syzkaller.appspot.com/bug?id=3ea507fb3c47426497b52bd82b8ef0dd5b6cc7ee
and, I believe, I recognized the problem. The problem appears in case of
ath9k_htc_hw_init() fail. In case of this fail all tx_buf->urb krefs will be
initialized to 1, but in free function:

static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)

....

static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
{
    ...
	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
				 &hif_dev->tx.tx_buf, list) {
		usb_get_urb(tx_buf->urb);
		...
		usb_free_urb(tx_buf->urb);
		...
		}

Krefs are incremented and then decremented, that means urbs won't be freed.
I found your patch and I can't properly understand why You added usb_get_urb(tx_buf->urb).
Can You explain please, I believe this will help me or somebody to fix this ussue :)

With regards,
Pavel Skripkin