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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	[thread overview]
Message-ID: <20210330193652.10642-1-paskripkin@gmail.com> (raw)
In-Reply-To: <20200911071427.32354-1-brookebasile@gmail.com>

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

  parent reply	other threads:[~2021-03-30 19:38 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-11  7:14 [PATCH] wireless: ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs() Brooke Basile
2020-09-20  2:03 ` Brooke Basile
2020-09-21 13:05 ` Kalle Valo
     [not found] ` <20200921130559.005D8C43382@smtp.codeaurora.org>
2020-09-21 23:04   ` Brooke Basile
2021-03-30 19:36 ` Pavel Skripkin [this message]
2021-03-31  6:28   ` Memory leak in ath9k_hif_usb_dealloc_tx_urbs() Greg KH
2021-04-27 11:35     ` Atul Gopinathan
2021-04-27 11:50       ` Greg KH
2021-04-27 12:04       ` Pavel Skripkin
2021-04-27 12:29         ` Pavel Skripkin
2021-04-27 13:01           ` Atul Gopinathan

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