On Fri, 2013-07-19 at 23:30 +0200, Richard Weinberger wrote:
> rhine_reset_task() misses to call netif_stop_queue(),
> this can lead to a crash if work is still scheduled while
> we're resetting the tx queue.
>
> Fixes:
> [ 93.591707] BUG: unable to handle kernel NULL pointer dereference at
> 0000004c
> [ 93.595514] IP: [<c119d10d>] rhine_napipoll+0x491/0x6e
>
> Signed-off-by: Richard Weinberger <rich...@nod.at>
> ---
> drivers/net/ethernet/via/via-rhine.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/ethernet/via/via-rhine.c
> b/drivers/net/ethernet/via/via-rhine.c
> index b75eb9e..57e1b40 100644
> --- a/drivers/net/ethernet/via/via-rhine.c
> +++ b/drivers/net/ethernet/via/via-rhine.c
> @@ -1615,6 +1615,7 @@ static void rhine_reset_task(struct work_struct *work)
> goto out_unlock;
>
> napi_disable(&rp->napi);
> + netif_stop_queue(dev);
This is not really fixing the bug because there is no synchronisation
with the TX scheduler. You can call netif_tx_disable() instead to do
that.
(I also think that it is preferable to use
netif_device_{detach,attach}() to stop the queue during reconfiguration,
as this is independent of TX completions and the watchdog.)
Ben.
> spin_lock_bh(&rp->lock);
>
> /* clear all descriptors */
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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