[PATCH net 0/2] net/sched: fix wrong behavior of MPLS push/pop action

[PATCH net 0/2] net/sched: fix wrong behavior of MPLS push/pop action

[Davide Caratti]

this series contains two fixes for TC 'act_mpls', that try to address
two problems that can be observed configuring simple 'push' / 'pop'
operations:
- patch 1/2 avoids dropping non-MPLS packets that pass through the MPLS
  'pop' action.
- patch 2/2 fixes corruption of the L2 header that occurs when 'push'
  or 'pop' actions are configured in TC egress path.

Davide Caratti (2):
  net: avoid errors when trying to pop MLPS header on non-MPLS packets
  net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

 include/linux/skbuff.h    |  5 +++--
 net/core/skbuff.c         | 20 +++++++++++---------
 net/openvswitch/actions.c |  5 +++--
 net/sched/act_mpls.c      | 12 ++++++++----
 4 files changed, 25 insertions(+), 17 deletions(-)

-- 
2.21.0

[PATCH net 1/2] net: avoid errors when trying to pop MLPS header on non-MPLS packets

[Davide Caratti]

the following script:

 # tc qdisc add dev eth0 clsact
 # tc filter add dev eth0 egress matchall action mpls pop

implicitly makes the kernel drop all packets transmitted by eth0, if they
don't have a MPLS header. This behavior is uncommon: other encapsulations
(like VLAN) just let the packet pass unmodified. Since the result of MPLS
'pop' operation would be the same regardless of the presence / absence of
MPLS header(s) in the original packet, we can let skb_mpls_pop() return 0
when dealing with non-MPLS packets.

Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 529133611ea2..cd59ccd6da57 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5536,7 +5536,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
 	int err;
 
 	if (unlikely(!eth_p_mpls(skb->protocol)))
-		return -EINVAL;
+		return 0;
 
 	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
 	if (unlikely(err))
-- 
2.21.0

[PATCH net 2/2] net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

[Davide Caratti]

the following script:

 # tc qdisc add dev eth0 clsact
 # tc filter add dev eth0 egress protocol ip matchall \
 > action mpls push protocol mpls_uc label 0x355aa bos 1

causes corruption of all IP packets transmitted by eth0. On TC egress, we
can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
operation will result in an overwrite of the first 4 octets in the packet
L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
error pattern is present also in the MPLS 'pop' operation. Fix this error
in act_mpls data plane, computing 'mac_len' as the difference between the
network header and the mac header (when not at TC ingress), and use it in
MPLS 'push'/'pop' core functions.

CC: Lorenzo Bianconi <lorenzo@kernel.org>
Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 include/linux/skbuff.h    |  5 +++--
 net/core/skbuff.c         | 18 ++++++++++--------
 net/openvswitch/actions.c |  5 +++--
 net/sched/act_mpls.c      | 12 ++++++++----
 4 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4351577b14d7..7914fdaf4226 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3510,8 +3510,9 @@ int skb_ensure_writable(struct sk_buff *skb, int write_len);
 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
 int skb_vlan_pop(struct sk_buff *skb);
 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
-int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto);
-int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto);
+int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
+		  int mac_len);
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len);
 int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse);
 int skb_mpls_dec_ttl(struct sk_buff *skb);
 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index cd59ccd6da57..ea88a65491a9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5477,12 +5477,14 @@ static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr,
  * @skb: buffer
  * @mpls_lse: MPLS label stack entry to push
  * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
+ * @mac_len: length of the MAC header
  *
  * Expects skb->data at mac header.
  *
  * Returns 0 on success, -errno otherwise.
  */
-int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto)
+int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
+		  int mac_len)
 {
 	struct mpls_shim_hdr *lse;
 	int err;
@@ -5499,15 +5501,15 @@ int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto)
 		return err;
 
 	if (!skb->inner_protocol) {
-		skb_set_inner_network_header(skb, skb->mac_len);
+		skb_set_inner_network_header(skb, mac_len);
 		skb_set_inner_protocol(skb, skb->protocol);
 	}
 
 	skb_push(skb, MPLS_HLEN);
 	memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
-		skb->mac_len);
+		mac_len);
 	skb_reset_mac_header(skb);
-	skb_set_network_header(skb, skb->mac_len);
+	skb_set_network_header(skb, mac_len);
 
 	lse = mpls_hdr(skb);
 	lse->label_stack_entry = mpls_lse;
@@ -5531,24 +5533,24 @@ EXPORT_SYMBOL_GPL(skb_mpls_push);
  *
  * Returns 0 on success, -errno otherwise.
  */
-int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len)
 {
 	int err;
 
 	if (unlikely(!eth_p_mpls(skb->protocol)))
 		return 0;
 
-	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
+	err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
 	if (unlikely(err))
 		return err;
 
 	skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
 	memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
-		skb->mac_len);
+		mac_len);
 
 	__skb_pull(skb, MPLS_HLEN);
 	skb_reset_mac_header(skb);
-	skb_set_network_header(skb, skb->mac_len);
+	skb_set_network_header(skb, mac_len);
 
 	if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
 		struct ethhdr *hdr;
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 3572e11b6f21..1c77f520f474 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -165,7 +165,8 @@ static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 {
 	int err;
 
-	err = skb_mpls_push(skb, mpls->mpls_lse, mpls->mpls_ethertype);
+	err = skb_mpls_push(skb, mpls->mpls_lse, mpls->mpls_ethertype,
+			    skb->mac_len);
 	if (err)
 		return err;
 
@@ -178,7 +179,7 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 {
 	int err;
 
-	err = skb_mpls_pop(skb, ethertype);
+	err = skb_mpls_pop(skb, ethertype, skb->mac_len);
 	if (err)
 		return err;
 
diff --git a/net/sched/act_mpls.c b/net/sched/act_mpls.c
index e168df0e008a..4cf6c553bb0b 100644
--- a/net/sched/act_mpls.c
+++ b/net/sched/act_mpls.c
@@ -55,7 +55,7 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
 	struct tcf_mpls *m = to_mpls(a);
 	struct tcf_mpls_params *p;
 	__be32 new_lse;
-	int ret;
+	int ret, mac_len;
 
 	tcf_lastuse_update(&m->tcf_tm);
 	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
@@ -63,8 +63,12 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
 	/* Ensure 'data' points at mac_header prior calling mpls manipulating
 	 * functions.
 	 */
-	if (skb_at_tc_ingress(skb))
+	if (skb_at_tc_ingress(skb)) {
 		skb_push_rcsum(skb, skb->mac_len);
+		mac_len = skb->mac_len;
+	} else {
+		mac_len = skb_network_header(skb) - skb_mac_header(skb);
+	}
 
 	ret = READ_ONCE(m->tcf_action);
 
@@ -72,12 +76,12 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
 
 	switch (p->tcfm_action) {
 	case TCA_MPLS_ACT_POP:
-		if (skb_mpls_pop(skb, p->tcfm_proto))
+		if (skb_mpls_pop(skb, p->tcfm_proto, mac_len))
 			goto drop;
 		break;
 	case TCA_MPLS_ACT_PUSH:
 		new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb->protocol));
-		if (skb_mpls_push(skb, new_lse, p->tcfm_proto))
+		if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len))
 			goto drop;
 		break;
 	case TCA_MPLS_ACT_MODIFY:
-- 
2.21.0

Re: [PATCH net 1/2] net: avoid errors when trying to pop MLPS header on non-MPLS packets

[Simon Horman]

On Thu, Oct 10, 2019 at 08:43:52PM +0200, Davide Caratti wrote:
> the following script:
> 
>  # tc qdisc add dev eth0 clsact
>  # tc filter add dev eth0 egress matchall action mpls pop
> 
> implicitly makes the kernel drop all packets transmitted by eth0, if they
> don't have a MPLS header. This behavior is uncommon: other encapsulations
> (like VLAN) just let the packet pass unmodified. Since the result of MPLS
> 'pop' operation would be the same regardless of the presence / absence of
> MPLS header(s) in the original packet, we can let skb_mpls_pop() return 0
> when dealing with non-MPLS packets.
> 
> Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Hi Davide,

For the TC use-case I think this is correct for the reasons you explain
above.

For the OVS use-case I also think it is fine because
__ovs_nla_copy_actions() will ensure that MPLS POP only occurs
for packets with an MPLS Ethernet protocol. That is, this condition
should never occur in that use-case.

And it appears that there are no other users of this function.

I think it might be worth adding something about use-cases other than TC
to the changelog, but that aside:

Reviewed-by: Simon Horman <simon.horman@netronome.com>

> ---
>  net/core/skbuff.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 529133611ea2..cd59ccd6da57 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -5536,7 +5536,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
>  	int err;
>  
>  	if (unlikely(!eth_p_mpls(skb->protocol)))
> -		return -EINVAL;
> +		return 0;
>  
>  	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
>  	if (unlikely(err))
> -- 
> 2.21.0
> 

Re: [PATCH net 2/2] net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

[Simon Horman]

On Thu, Oct 10, 2019 at 08:43:53PM +0200, Davide Caratti wrote:
> the following script:
> 
>  # tc qdisc add dev eth0 clsact
>  # tc filter add dev eth0 egress protocol ip matchall \
>  > action mpls push protocol mpls_uc label 0x355aa bos 1
> 
> causes corruption of all IP packets transmitted by eth0. On TC egress, we
> can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
> operation will result in an overwrite of the first 4 octets in the packet
> L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
> error pattern is present also in the MPLS 'pop' operation. Fix this error
> in act_mpls data plane, computing 'mac_len' as the difference between the
> network header and the mac header (when not at TC ingress), and use it in
> MPLS 'push'/'pop' core functions.
> 
> CC: Lorenzo Bianconi <lorenzo@kernel.org>
> Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Reviewed-by: Simon Horman <simon.horman@netronome.com>

Re: [PATCH net 1/2] net: avoid errors when trying to pop MLPS header on non-MPLS packets

[John Hurley]

On Fri, Oct 11, 2019 at 8:34 AM Simon Horman <simon.horman@netronome.com> wrote:
>
> On Thu, Oct 10, 2019 at 08:43:52PM +0200, Davide Caratti wrote:
> > the following script:
> >
> >  # tc qdisc add dev eth0 clsact
> >  # tc filter add dev eth0 egress matchall action mpls pop
> >
> > implicitly makes the kernel drop all packets transmitted by eth0, if they
> > don't have a MPLS header. This behavior is uncommon: other encapsulations
> > (like VLAN) just let the packet pass unmodified. Since the result of MPLS
> > 'pop' operation would be the same regardless of the presence / absence of
> > MPLS header(s) in the original packet, we can let skb_mpls_pop() return 0
> > when dealing with non-MPLS packets.
> >
> > Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> > Signed-off-by: Davide Caratti <dcaratti@redhat.com>
>

Acked-by: John Hurley <john.hurley@netronome.com>

> Hi Davide,
>
> For the TC use-case I think this is correct for the reasons you explain
> above.
>
> For the OVS use-case I also think it is fine because
> __ovs_nla_copy_actions() will ensure that MPLS POP only occurs
> for packets with an MPLS Ethernet protocol. That is, this condition
> should never occur in that use-case.
>
> And it appears that there are no other users of this function.
>
> I think it might be worth adding something about use-cases other than TC
> to the changelog, but that aside:
>
> Reviewed-by: Simon Horman <simon.horman@netronome.com>
>
> > ---
> >  net/core/skbuff.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> > index 529133611ea2..cd59ccd6da57 100644
> > --- a/net/core/skbuff.c
> > +++ b/net/core/skbuff.c
> > @@ -5536,7 +5536,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
> >       int err;
> >
> >       if (unlikely(!eth_p_mpls(skb->protocol)))
> > -             return -EINVAL;
> > +             return 0;
> >
> >       err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
> >       if (unlikely(err))
> > --
> > 2.21.0
> >

Re: [PATCH net 2/2] net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

[John Hurley]

On Fri, Oct 11, 2019 at 8:34 AM Simon Horman <simon.horman@netronome.com> wrote:
>
> On Thu, Oct 10, 2019 at 08:43:53PM +0200, Davide Caratti wrote:
> > the following script:
> >
> >  # tc qdisc add dev eth0 clsact
> >  # tc filter add dev eth0 egress protocol ip matchall \
> >  > action mpls push protocol mpls_uc label 0x355aa bos 1
> >
> > causes corruption of all IP packets transmitted by eth0. On TC egress, we
> > can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
> > operation will result in an overwrite of the first 4 octets in the packet
> > L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
> > error pattern is present also in the MPLS 'pop' operation. Fix this error
> > in act_mpls data plane, computing 'mac_len' as the difference between the
> > network header and the mac header (when not at TC ingress), and use it in
> > MPLS 'push'/'pop' core functions.
> >
> > CC: Lorenzo Bianconi <lorenzo@kernel.org>
> > Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> > Signed-off-by: Davide Caratti <dcaratti@redhat.com>
>


> Reviewed-by: Simon Horman <simon.horman@netronome.com>
>

Re: [PATCH net 2/2] net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

[John Hurley]

On Fri, Oct 11, 2019 at 8:34 AM Simon Horman <simon.horman@netronome.com> wrote:
>
> On Thu, Oct 10, 2019 at 08:43:53PM +0200, Davide Caratti wrote:
> > the following script:
> >
> >  # tc qdisc add dev eth0 clsact
> >  # tc filter add dev eth0 egress protocol ip matchall \
> >  > action mpls push protocol mpls_uc label 0x355aa bos 1
> >
> > causes corruption of all IP packets transmitted by eth0. On TC egress, we
> > can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
> > operation will result in an overwrite of the first 4 octets in the packet
> > L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
> > error pattern is present also in the MPLS 'pop' operation. Fix this error
> > in act_mpls data plane, computing 'mac_len' as the difference between the
> > network header and the mac header (when not at TC ingress), and use it in
> > MPLS 'push'/'pop' core functions.
> >
> > CC: Lorenzo Bianconi <lorenzo@kernel.org>
> > Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> > Signed-off-by: Davide Caratti <dcaratti@redhat.com>
>

Acked-by: John Hurley <john.hurley@netronome.com>

> Reviewed-by: Simon Horman <simon.horman@netronome.com>
>

Re: [PATCH net 2/2] net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 26253 bytes --]

Hi Davide,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net/master]

url:    https://github.com/0day-ci/linux/commits/Davide-Caratti/net-avoid-errors-when-trying-to-pop-MLPS-header-on-non-MPLS-packets/20191012-085439
reproduce: make htmldocs

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:546: warning: Function parameter or member 'vm' not described in 'for_each_amdgpu_vm_pt_dfs_safe'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:546: warning: Function parameter or member 'start' not described in 'for_each_amdgpu_vm_pt_dfs_safe'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:546: warning: Function parameter or member 'cursor' not described in 'for_each_amdgpu_vm_pt_dfs_safe'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:546: warning: Function parameter or member 'entry' not described in 'for_each_amdgpu_vm_pt_dfs_safe'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:821: warning: Function parameter or member 'level' not described in 'amdgpu_vm_bo_param'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'params' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'bo' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'level' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'pe' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'addr' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'count' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'incr' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:1283: warning: Function parameter or member 'flags' not described in 'amdgpu_vm_update_flags'
   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:2821: warning: Function parameter or member 'pasid' not described in 'amdgpu_vm_make_compute'
   drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c:378: warning: Excess function parameter 'entry' description in 'amdgpu_irq_dispatch'
   drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c:379: warning: Function parameter or member 'ih' not described in 'amdgpu_irq_dispatch'
   drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c:379: warning: Excess function parameter 'entry' description in 'amdgpu_irq_dispatch'
   drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c:1: warning: no structured comments found
   drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1: warning: no structured comments found
   drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c:1: warning: 'pp_dpm_sclk pp_dpm_mclk pp_dpm_pcie' not found
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:132: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source @atomic_obj
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:238: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source gpu_info FW provided soc bounding box struct or 0 if not
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'atomic_obj' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'backlight_link' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'backlight_caps' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'freesync_module' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'fw_dmcu' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'dmcu_fw_version' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h:243: warning: Function parameter or member 'soc_bounding_box' not described in 'amdgpu_display_manager'
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1: warning: 'register_hpd_handlers' not found
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1: warning: 'dm_crtc_high_irq' not found
   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:1: warning: 'dm_pflip_high_irq' not found
   drivers/gpio/gpiolib-of.c:92: warning: Excess function parameter 'dev' description in 'of_gpio_need_valid_mask'
   include/linux/i2c.h:337: warning: Function parameter or member 'init_irq' not described in 'i2c_client'
   mm/util.c:1: warning: 'get_user_pages_fast' not found
   mm/slab.c:4215: warning: Function parameter or member 'objp' not described in '__ksize'
   fs/fs-writeback.c:913: warning: Excess function parameter 'nr_pages' description in 'cgroup_writeback_by_id'
   fs/direct-io.c:258: warning: Excess function parameter 'offset' description in 'dio_complete'
   fs/libfs.c:496: warning: Excess function parameter 'available' description in 'simple_write_end'
   fs/posix_acl.c:647: warning: Function parameter or member 'inode' not described in 'posix_acl_update_mode'
   fs/posix_acl.c:647: warning: Function parameter or member 'mode_p' not described in 'posix_acl_update_mode'
   fs/posix_acl.c:647: warning: Function parameter or member 'acl' not described in 'posix_acl_update_mode'
   drivers/usb/typec/bus.c:1: warning: 'typec_altmode_register_driver' not found
   drivers/usb/typec/bus.c:1: warning: 'typec_altmode_unregister_driver' not found
   drivers/usb/typec/class.c:1: warning: 'typec_altmode_unregister_notifier' not found
   drivers/usb/typec/class.c:1: warning: 'typec_altmode_register_notifier' not found
   include/linux/w1.h:277: warning: Function parameter or member 'of_match_table' not described in 'w1_family'
   kernel/dma/coherent.c:1: warning: no structured comments found
   include/linux/input/sparse-keymap.h:43: warning: Function parameter or member 'sw' not described in 'key_entry'
   lib/genalloc.c:1: warning: 'gen_pool_add_virt' not found
   lib/genalloc.c:1: warning: 'gen_pool_alloc' not found
   lib/genalloc.c:1: warning: 'gen_pool_free' not found
   lib/genalloc.c:1: warning: 'gen_pool_alloc_algo' not found
   include/linux/bitmap.h:341: warning: Function parameter or member 'nbits' not described in 'bitmap_or_equal'
   include/linux/rculist.h:374: warning: Excess function parameter 'cond' description in 'list_for_each_entry_rcu'
   include/linux/rculist.h:651: warning: Excess function parameter 'cond' description in 'hlist_for_each_entry_rcu'
   include/net/mac80211.h:4056: warning: Function parameter or member 'sta_set_txpwr' not described in 'ieee80211_ops'
   include/net/mac80211.h:2018: warning: Function parameter or member 'txpwr' not described in 'ieee80211_sta'
   include/net/cfg80211.h:1185: warning: Function parameter or member 'txpwr' not described in 'station_parameters'
   include/linux/skbuff.h:888: warning: Function parameter or member 'dev_scratch' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'list' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'ip_defrag_offset' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'skb_mstamp_ns' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member '__cloned_offset' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'head_frag' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member '__pkt_type_offset' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'encapsulation' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'encap_hdr_csum' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'csum_valid' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member '__pkt_vlan_present_offset' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'vlan_present' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'csum_complete_sw' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'csum_level' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'inner_protocol_type' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'remcsum_offload' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'sender_cpu' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'reserved_tailroom' not described in 'sk_buff'
   include/linux/skbuff.h:888: warning: Function parameter or member 'inner_ipproto' not described in 'sk_buff'
   include/net/sock.h:233: warning: Function parameter or member 'skc_addrpair' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_portpair' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_ipv6only' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_net_refcnt' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_v6_daddr' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_v6_rcv_saddr' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_cookie' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_listener' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_tw_dr' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_rcv_wnd' not described in 'sock_common'
   include/net/sock.h:233: warning: Function parameter or member 'skc_tw_rcv_nxt' not described in 'sock_common'
   include/net/sock.h:515: warning: Function parameter or member 'sk_rx_skb_cache' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_wq_raw' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'tcp_rtx_queue' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_tx_skb_cache' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_route_forced_caps' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_txtime_report_errors' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_validate_xmit_skb' not described in 'sock'
   include/net/sock.h:515: warning: Function parameter or member 'sk_bpf_storage' not described in 'sock'
   include/net/sock.h:2441: warning: Function parameter or member 'tcp_rx_skb_cache_key' not described in 'DECLARE_STATIC_KEY_FALSE'
   include/net/sock.h:2441: warning: Excess function parameter 'sk' description in 'DECLARE_STATIC_KEY_FALSE'
   include/net/sock.h:2441: warning: Excess function parameter 'skb' description in 'DECLARE_STATIC_KEY_FALSE'
>> net/core/skbuff.c:5538: warning: Function parameter or member 'mac_len' not described in 'skb_mpls_pop'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'gso_partial_features' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'l3mdev_ops' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'xfrmdev_ops' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'tlsdev_ops' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'name_assign_type' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'ieee802154_ptr' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'mpls_ptr' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'xdp_prog' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'gro_flush_timeout' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'nf_hooks_ingress' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member '____cacheline_aligned_in_smp' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'qdisc_hash' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'xps_cpus_map' not described in 'net_device'
   include/linux/netdevice.h:2053: warning: Function parameter or member 'xps_rxqs_map' not described in 'net_device'
   include/linux/phylink.h:56: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising' not described in 'phylink_link_state'
   include/linux/phylink.h:56: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising' not described in 'phylink_link_state'
   include/drm/drm_modeset_helper_vtables.h:1053: warning: Function parameter or member 'prepare_writeback_job' not described in 'drm_connector_helper_funcs'
   include/drm/drm_modeset_helper_vtables.h:1053: warning: Function parameter or member 'cleanup_writeback_job' not described in 'drm_connector_helper_funcs'
   include/drm/drm_atomic_state_helper.h:1: warning: no structured comments found
   include/drm/drm_gem_shmem_helper.h:87: warning: Function parameter or member 'madv' not described in 'drm_gem_shmem_object'
   include/drm/drm_gem_shmem_helper.h:87: warning: Function parameter or member 'madv_list' not described in 'drm_gem_shmem_object'
   drivers/gpu/drm/i915/display/intel_dpll_mgr.h:158: warning: Enum value 'DPLL_ID_TGL_MGPLL5' not described in enum 'intel_dpll_id'
   drivers/gpu/drm/i915/display/intel_dpll_mgr.h:158: warning: Enum value 'DPLL_ID_TGL_MGPLL6' not described in enum 'intel_dpll_id'
   drivers/gpu/drm/i915/display/intel_dpll_mgr.h:158: warning: Excess enum value 'DPLL_ID_TGL_TCPLL6' description in 'intel_dpll_id'
   drivers/gpu/drm/i915/display/intel_dpll_mgr.h:158: warning: Excess enum value 'DPLL_ID_TGL_TCPLL5' description in 'intel_dpll_id'
   drivers/gpu/drm/i915/display/intel_dpll_mgr.h:342: warning: Function parameter or member 'wakeref' not described in 'intel_shared_dpll'
   Error: Cannot open file drivers/gpu/drm/i915/i915_gem_batch_pool.c
   Error: Cannot open file drivers/gpu/drm/i915/i915_gem_batch_pool.c
   Error: Cannot open file drivers/gpu/drm/i915/i915_gem_batch_pool.c
   drivers/gpu/drm/i915/i915_drv.h:1129: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source The OA context specific information.
   drivers/gpu/drm/i915/i915_drv.h:1143: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source State of the OA buffer.
   drivers/gpu/drm/i915/i915_drv.h:1154: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Locks reads and writes to all head/tail state
   drivers/gpu/drm/i915/i915_drv.h:1176: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source One 'aging' tail pointer and one 'aged' tail pointer ready to
   drivers/gpu/drm/i915/i915_drv.h:1188: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Index for the aged tail ready to read() data up to.
   drivers/gpu/drm/i915/i915_drv.h:1193: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source A monotonic timestamp for when the current aging tail pointer
   drivers/gpu/drm/i915/i915_drv.h:1199: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Although we can always read back the head pointer register,
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'pinned_ctx' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'specific_ctx_id' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'specific_ctx_id_mask' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'poll_check_timer' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'poll_wq' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'pollin' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'periodic' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'period_exponent' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1207: warning: Function parameter or member 'oa_buffer' not described in 'i915_perf_stream'
   drivers/gpu/drm/i915/i915_drv.h:1129: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source The OA context specific information.
   drivers/gpu/drm/i915/i915_drv.h:1143: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source State of the OA buffer.
   drivers/gpu/drm/i915/i915_drv.h:1154: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Locks reads and writes to all head/tail state
   drivers/gpu/drm/i915/i915_drv.h:1176: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source One 'aging' tail pointer and one 'aged' tail pointer ready to
   drivers/gpu/drm/i915/i915_drv.h:1188: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Index for the aged tail ready to read() data up to.
   drivers/gpu/drm/i915/i915_drv.h:1193: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source A monotonic timestamp for when the current aging tail pointer
   drivers/gpu/drm/i915/i915_drv.h:1199: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Although we can always read back the head pointer register,
   drivers/gpu/drm/i915/i915_drv.h:1129: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source The OA context specific information.
   drivers/gpu/drm/i915/i915_drv.h:1143: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source State of the OA buffer.
   drivers/gpu/drm/i915/i915_drv.h:1154: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Locks reads and writes to all head/tail state
   drivers/gpu/drm/i915/i915_drv.h:1176: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source One 'aging' tail pointer and one 'aged' tail pointer ready to
   drivers/gpu/drm/i915/i915_drv.h:1188: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Index for the aged tail ready to read() data up to.
   drivers/gpu/drm/i915/i915_drv.h:1193: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source A monotonic timestamp for when the current aging tail pointer
   drivers/gpu/drm/i915/i915_drv.h:1199: warning: Incorrect use of kernel-doc format: Documentation Makefile include scripts source Although we can always read back the head pointer register,
   drivers/gpu/drm/mcde/mcde_drv.c:1: warning: 'ST-Ericsson MCDE DRM Driver' not found
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'quotactl' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'quota_on' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'sb_free_mnt_opts' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'sb_eat_lsm_opts' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'sb_kern_mount' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'sb_show_options' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'sb_add_mnt_opt' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'd_instantiate' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'getprocattr' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'setprocattr' not described in 'security_list_options'
   include/linux/lsm_hooks.h:1822: warning: Function parameter or member 'locked_down' not described in 'security_list_options'
   Documentation/admin-guide/perf/imx-ddr.rst:21: WARNING: Unexpected indentation.
   Documentation/admin-guide/perf/imx-ddr.rst:34: WARNING: Unexpected indentation.
   Documentation/admin-guide/perf/imx-ddr.rst:40: WARNING: Unexpected indentation.
   Documentation/admin-guide/perf/imx-ddr.rst:45: WARNING: Unexpected indentation.
   Documentation/admin-guide/perf/imx-ddr.rst:52: WARNING: Unexpected indentation.
   Documentation/admin-guide/xfs.rst:257: WARNING: Block quote ends without a blank line; unexpected unindent.
   Documentation/arm64/memory.rst:158: WARNING: Unexpected indentation.
   Documentation/arm64/memory.rst:162: WARNING: Unexpected indentation.
   Documentation/hwmon/inspur-ipsps1.rst:2: WARNING: Title underline too short.

vim +5538 net/core/skbuff.c

8822e270d69701 John Hurley    2019-07-07  5525  
ed246cee09b986 John Hurley    2019-07-07  5526  /**
ed246cee09b986 John Hurley    2019-07-07  5527   * skb_mpls_pop() - pop the outermost MPLS header
ed246cee09b986 John Hurley    2019-07-07  5528   *
ed246cee09b986 John Hurley    2019-07-07  5529   * @skb: buffer
ed246cee09b986 John Hurley    2019-07-07  5530   * @next_proto: ethertype of header after popped MPLS header
ed246cee09b986 John Hurley    2019-07-07  5531   *
ed246cee09b986 John Hurley    2019-07-07  5532   * Expects skb->data at mac header.
ed246cee09b986 John Hurley    2019-07-07  5533   *
ed246cee09b986 John Hurley    2019-07-07  5534   * Returns 0 on success, -errno otherwise.
ed246cee09b986 John Hurley    2019-07-07  5535   */
c3fa3a45784aab Davide Caratti 2019-10-10  5536  int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len)
ed246cee09b986 John Hurley    2019-07-07  5537  {
ed246cee09b986 John Hurley    2019-07-07 @5538  	int err;
ed246cee09b986 John Hurley    2019-07-07  5539  
ed246cee09b986 John Hurley    2019-07-07  5540  	if (unlikely(!eth_p_mpls(skb->protocol)))
4fa3379002f6b6 Davide Caratti 2019-10-10  5541  		return 0;
ed246cee09b986 John Hurley    2019-07-07  5542  
c3fa3a45784aab Davide Caratti 2019-10-10  5543  	err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
ed246cee09b986 John Hurley    2019-07-07  5544  	if (unlikely(err))
ed246cee09b986 John Hurley    2019-07-07  5545  		return err;
ed246cee09b986 John Hurley    2019-07-07  5546  
ed246cee09b986 John Hurley    2019-07-07  5547  	skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
ed246cee09b986 John Hurley    2019-07-07  5548  	memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
c3fa3a45784aab Davide Caratti 2019-10-10  5549  		mac_len);
ed246cee09b986 John Hurley    2019-07-07  5550  
ed246cee09b986 John Hurley    2019-07-07  5551  	__skb_pull(skb, MPLS_HLEN);
ed246cee09b986 John Hurley    2019-07-07  5552  	skb_reset_mac_header(skb);
c3fa3a45784aab Davide Caratti 2019-10-10  5553  	skb_set_network_header(skb, mac_len);
ed246cee09b986 John Hurley    2019-07-07  5554  
ed246cee09b986 John Hurley    2019-07-07  5555  	if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
ed246cee09b986 John Hurley    2019-07-07  5556  		struct ethhdr *hdr;
ed246cee09b986 John Hurley    2019-07-07  5557  
ed246cee09b986 John Hurley    2019-07-07  5558  		/* use mpls_hdr() to get ethertype to account for VLANs. */
ed246cee09b986 John Hurley    2019-07-07  5559  		hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
ed246cee09b986 John Hurley    2019-07-07  5560  		skb_mod_eth_type(skb, hdr, next_proto);
ed246cee09b986 John Hurley    2019-07-07  5561  	}
ed246cee09b986 John Hurley    2019-07-07  5562  	skb->protocol = next_proto;
ed246cee09b986 John Hurley    2019-07-07  5563  
ed246cee09b986 John Hurley    2019-07-07  5564  	return 0;
ed246cee09b986 John Hurley    2019-07-07  5565  }
ed246cee09b986 John Hurley    2019-07-07  5566  EXPORT_SYMBOL_GPL(skb_mpls_pop);
ed246cee09b986 John Hurley    2019-07-07  5567  

:::::: The code at line 5538 was first introduced by commit
:::::: ed246cee09b9865145a2e1e34f63ec0e31dd83a5 net: core: move pop MPLS functionality from OvS to core helper

:::::: TO: John Hurley <john.hurley@netronome.com>
:::::: CC: David S. Miller <davem@davemloft.net>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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