From: Eric Dumazet <eric.duma...@gmail.com> Sent: Wednesday, January 18, 2017
12:36 PM
>To: Ashizuka, Yuusuke <ashid...@jp.fujitsu.com>
>Cc: Andy Duan <fugang.d...@nxp.com>; netdev@vger.kernel.org; Pravin B
>Shelar <pshe...@nicira.com>
>Subject: Re: [PATCH] net: fec: Fixed panic problem with non-tso
>
>On Tue, 2017-01-17 at 20:21 -0800, Eric Dumazet wrote:
>> On Wed, 2017-01-18 at 03:12 +0000, Ashizuka, Yuusuke wrote:
>>
>> > indeed.
>> >
>> > In the case of TSO with i.MX6 system (highmem enabled) with 2GB
>> > memory, "this_frag->page.p" did not become highmem area.
>> > (We confirmed by transferring about 100MB of files)
>> >
>> > However, in the case of non-tso on an i.MX6 system with 2GB of
>> > memory, "this_frag->page.p" may become a highmem area.
>> > (Occurred with approximately 2MB of file transfer)
>> >
>> > For non-tso only, I do not know the reason why "this_frag-> page.p"
>> > in this driver shows highmem area.
>>
>> This worries me, since this driver does not set NETIF_F_HIGHDMA in its
>> features.
>>
>> No packet should be given to this driver with a highmem fragment
>>
>> Check is done in illegal_highdma() in net/core/dev.c
>
>This used to work.
>
>I suspect commit ec5f061564238892005257c83565a0b58ec79295
>("net: Kill link between CSUM and SG features.")
>
>added this bug.
>
>Can you try this hot fix :
>
>diff --git a/net/core/dev.c b/net/core/dev.c index
>ad5959e561166f445bdd9d7260652a338f74cfea..073b832b945257dba9ed47f4bf
>875605225effc9 100644
>--- a/net/core/dev.c
>+++ b/net/core/dev.c
>@@ -2773,9 +2773,9 @@ static netdev_features_t harmonize_features(struct
>sk_buff *skb,
> if (skb->ip_summed != CHECKSUM_NONE &&
> !can_checksum_protocol(features, type)) {
> features &= ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
>- } else if (illegal_highdma(skb->dev, skb)) {
>- features &= ~NETIF_F_SG;
> }
>+ if (illegal_highdma(skb->dev, skb))
>+ features &= ~NETIF_F_SG;
>
> return features;
> }
>
>
I will double check your fix. Thanks.
And, if driver is to support highmem, then we should add tso highmem support
in net/core/tso.c, do you think it is necessary ?
