Re: [PATCH v3 1/4] can: kvaser_usb: Don't free packets when tight on URBs

Marc Kleine-Budde
2015-01-08T09:59:55Z

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On 01/05/2015 06:49 PM, Ahmed S. Darwish wrote:
> From: Ahmed S. Darwish <ahmed.darwish@valeo.com>
>
> Flooding the Kvaser CAN to USB dongle with multiple reads and
> writes in high frequency caused seemingly-random panics in the
> kernel.
>
> On further inspection, it seems the driver erroneously freed the
> to-be-transmitted packet upon getting tight on URBs and returning
> NETDEV_TX_BUSY, leading to invalid memory writes and double frees
> at a later point in time.
>
> Note:
>
> Finding no more URBs/transmit-contexts and returning NETDEV_TX_BUSY
> is a driver bug in and out of itself: it means that our start/stop
> queue flow control is broken.
>
> This patch only fixes the (buggy) error handling code; the root
> cause shall be fixed in a later commit.
>
> Signed-off-by: Ahmed S. Darwish <ahmed.darwish@valeo.com>
> Acked-by: Olivier Sobrie <olivier@sobrie.be>

Applied 1-3 to can/master + added stable on Cc.

Marc

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