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From: Fedor Pchelkin <>
To: "Toke Høiland-Jørgensen" <>, "Kalle Valo" <>
Cc: Fedor Pchelkin <>,
	"David S. Miller" <>,
	Eric Dumazet <>,
	Jakub Kicinski <>, Paolo Abeni <>,
	Zekun Shen <>, Joe Perches <>,
	"John W. Linville" <>,,,,
	Alexey Khoroshilov <>,
Subject: Re: [PATCH v2] wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails
Date: Wed,  4 Jan 2023 01:30:52 +0300	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

> Hmm, so in the other error cases (if SKB allocation fails), we just
> 'goto err' and call the receive handler for the packets already in
> skb_pool. Why can't we do the same here?

If SKB allocation fails, then the packets already in skb_pool should be
processed by htc rx handler, yes. About the other two cases: if pkt_tag or
pkt_len is invalid, then the whole SKB is considered invalid and dropped.
That is what the statistics macros tell. So I think we should not process
packets from skb_pool which are associated with a dropped SKB. And so just
free them instead.

> Also, I think there's another bug in that function, which this change
> will make worse? Specifically, in the start of that function,
> hif_dev->remain_skb is moved to skb_pool[0], but not cleared from
> hif_dev itself. So if we then hit the invalid check and free it, the
> next time the function is called, we'll get the same remain_skb pointer,
> which has now been freed.

Sorry, I missed that somehow.
Moving 'hif_dev->rx_remain_len = index - MAX_RX_BUF_SIZE;' after
"ath9k_htc: RX memory allocation error\n" error path should be done, too.
hif_dev->rx_remain_len is zeroed after remain_skb processing, so we cannot
reference hif_dev->remain_skb unless we explicitly allocate successfully a
new one (making rx_remain_len non zero).

> So I think we'll need to clear out hif_dev->remain_skb after moving it
> to skb_pool. Care to add that as well?

Yes, this must be done. I'll add it to patch v3.

  reply	other threads:[~2023-01-03 22:31 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-28 22:40 [PATCH] wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails Fedor Pchelkin
2023-01-02 10:52 ` Toke Høiland-Jørgensen
2023-01-03 14:29   ` Fedor Pchelkin
2023-01-03 20:18     ` Toke Høiland-Jørgensen
2023-01-03 14:30   ` [PATCH v2] " Fedor Pchelkin
2023-01-03 21:03     ` Toke Høiland-Jørgensen
2023-01-03 22:30       ` Fedor Pchelkin [this message]
2023-01-03 23:38         ` Toke Høiland-Jørgensen
2023-01-04 12:36           ` [PATCH v3] " Fedor Pchelkin
2023-01-04 14:50             ` Toke Høiland-Jørgensen
2023-01-17 11:53             ` Kalle Valo

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