2021-02-22 03:18:54

by Yejune Deng

[permalink] [raw]
Subject: [PATCH] arp: Remove the arp_hh_ops structure

The arp_hh_ops structure is similar to the arp_generic_ops structure.
but the latter is more general,so remove the arp_hh_ops structure.

Fix when took out the neigh->ops assignment:
8.973653] #PF: supervisor read access in kernel mode
[ 8.975027] #PF: error_code(0x0000) - not-present page
[ 8.976310] PGD 0 P4D 0
[ 8.977036] Oops: 0000 [#1] SMP PTI
[ 8.977973] CPU: 1 PID: 210 Comm: sd-resolve Not tainted 5.11.0-rc7-02046-g4591591ab715 #1
[ 8.979998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 8.981996] RIP: 0010:neigh_probe (kbuild/src/consumer/net/core/neighbour.c:1009)

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Yejune Deng <[email protected]>
---
net/ipv4/arp.c | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 922dd73e5740..9ee59c2e419a 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -135,14 +135,6 @@ static const struct neigh_ops arp_generic_ops = {
.connected_output = neigh_connected_output,
};

-static const struct neigh_ops arp_hh_ops = {
- .family = AF_INET,
- .solicit = arp_solicit,
- .error_report = arp_error_report,
- .output = neigh_resolve_output,
- .connected_output = neigh_resolve_output,
-};
-
static const struct neigh_ops arp_direct_ops = {
.family = AF_INET,
.output = neigh_direct_output,
@@ -277,12 +269,9 @@ static int arp_constructor(struct neighbour *neigh)
memcpy(neigh->ha, dev->broadcast, dev->addr_len);
}

- if (dev->header_ops->cache)
- neigh->ops = &arp_hh_ops;
- else
- neigh->ops = &arp_generic_ops;
+ neigh->ops = &arp_generic_ops;

- if (neigh->nud_state & NUD_VALID)
+ if (!dev->header_ops->cache && (neigh->nud_state & NUD_VALID))
neigh->output = neigh->ops->connected_output;
else
neigh->output = neigh->ops->output;
--
2.29.0


2021-02-22 08:40:08

by Eric Dumazet

[permalink] [raw]
Subject: Re: [PATCH] arp: Remove the arp_hh_ops structure



On 2/22/21 4:15 AM, Yejune Deng wrote:
> The arp_hh_ops structure is similar to the arp_generic_ops structure.
> but the latter is more general,so remove the arp_hh_ops structure.
>
> Fix when took out the neigh->ops assignment:
> 8.973653] #PF: supervisor read access in kernel mode
> [ 8.975027] #PF: error_code(0x0000) - not-present page
> [ 8.976310] PGD 0 P4D 0
> [ 8.977036] Oops: 0000 [#1] SMP PTI
> [ 8.977973] CPU: 1 PID: 210 Comm: sd-resolve Not tainted 5.11.0-rc7-02046-g4591591ab715 #1
> [ 8.979998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
> [ 8.981996] RIP: 0010:neigh_probe (kbuild/src/consumer/net/core/neighbour.c:1009)
>

I have a hard time understanding this patch submission.

This seems a mix of a net-next and net material ?



> Reported-by: kernel test robot <[email protected]>

If this is a bug fix, we want a Fixes: tag

This will really help us. Please don't let us guess what is going on.


Also, if this is not a bug fix, this should target net-next tree,
please take a look at Documentation/networking/netdev-FAQ.rst

In short, the stack trace in this changelog seems to be not
related to this patch, maybe a prior version ? We do not want
to keep artifacts of some buggy version that was never merged
into official tree.

Thanks.

> Signed-off-by: Yejune Deng <[email protected]>
> ---
> net/ipv4/arp.c | 15 ++-------------
> 1 file changed, 2 insertions(+), 13 deletions(-)
>
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 922dd73e5740..9ee59c2e419a 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -135,14 +135,6 @@ static const struct neigh_ops arp_generic_ops = {
> .connected_output = neigh_connected_output,
> };
>
> -static const struct neigh_ops arp_hh_ops = {
> - .family = AF_INET,
> - .solicit = arp_solicit,
> - .error_report = arp_error_report,
> - .output = neigh_resolve_output,
> - .connected_output = neigh_resolve_output,
> -};
> -
> static const struct neigh_ops arp_direct_ops = {
> .family = AF_INET,
> .output = neigh_direct_output,
> @@ -277,12 +269,9 @@ static int arp_constructor(struct neighbour *neigh)
> memcpy(neigh->ha, dev->broadcast, dev->addr_len);
> }
>
> - if (dev->header_ops->cache)
> - neigh->ops = &arp_hh_ops;
> - else
> - neigh->ops = &arp_generic_ops;
> + neigh->ops = &arp_generic_ops;
>
> - if (neigh->nud_state & NUD_VALID)
> + if (!dev->header_ops->cache && (neigh->nud_state & NUD_VALID))
> neigh->output = neigh->ops->connected_output;
> else
> neigh->output = neigh->ops->output;
>

2021-02-22 16:13:36

by David Ahern

[permalink] [raw]
Subject: Re: [PATCH] arp: Remove the arp_hh_ops structure

On 2/22/21 1:37 AM, Eric Dumazet wrote:
>
>
> On 2/22/21 4:15 AM, Yejune Deng wrote:
>> The arp_hh_ops structure is similar to the arp_generic_ops structure.
>> but the latter is more general,so remove the arp_hh_ops structure.
>>
>> Fix when took out the neigh->ops assignment:
>> 8.973653] #PF: supervisor read access in kernel mode
>> [ 8.975027] #PF: error_code(0x0000) - not-present page
>> [ 8.976310] PGD 0 P4D 0
>> [ 8.977036] Oops: 0000 [#1] SMP PTI
>> [ 8.977973] CPU: 1 PID: 210 Comm: sd-resolve Not tainted 5.11.0-rc7-02046-g4591591ab715 #1
>> [ 8.979998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
>> [ 8.981996] RIP: 0010:neigh_probe (kbuild/src/consumer/net/core/neighbour.c:1009)
>>
>
> I have a hard time understanding this patch submission.
>
> This seems a mix of a net-next and net material ?

It is net-next at best.

>
>
>
>> Reported-by: kernel test robot <[email protected]>
>
> If this is a bug fix, we want a Fixes: tag
>
> This will really help us. Please don't let us guess what is going on.
>

This patch is a v2. v1 was clearly wrong and not tested; I responded as
such 12 hours before the robot test.

2021-02-23 07:04:08

by Yejune Deng

[permalink] [raw]
Subject: Re: [PATCH] arp: Remove the arp_hh_ops structure

Thank you for the clarification.

On Tue, Feb 23, 2021 at 12:07 AM David Ahern <[email protected]> wrote:
>
> On 2/22/21 1:37 AM, Eric Dumazet wrote:
> >
> >
> > On 2/22/21 4:15 AM, Yejune Deng wrote:
> >> The arp_hh_ops structure is similar to the arp_generic_ops structure.
> >> but the latter is more general,so remove the arp_hh_ops structure.
> >>
> >> Fix when took out the neigh->ops assignment:
> >> 8.973653] #PF: supervisor read access in kernel mode
> >> [ 8.975027] #PF: error_code(0x0000) - not-present page
> >> [ 8.976310] PGD 0 P4D 0
> >> [ 8.977036] Oops: 0000 [#1] SMP PTI
> >> [ 8.977973] CPU: 1 PID: 210 Comm: sd-resolve Not tainted 5.11.0-rc7-02046-g4591591ab715 #1
> >> [ 8.979998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
> >> [ 8.981996] RIP: 0010:neigh_probe (kbuild/src/consumer/net/core/neighbour.c:1009)
> >>
> >
> > I have a hard time understanding this patch submission.
> >
> > This seems a mix of a net-next and net material ?
>
> It is net-next at best.
>
> >
> >
> >
> >> Reported-by: kernel test robot <[email protected]>
> >
> > If this is a bug fix, we want a Fixes: tag
> >
> > This will really help us. Please don't let us guess what is going on.
> >
>
> This patch is a v2. v1 was clearly wrong and not tested; I responded as
> such 12 hours before the robot test.