Commit dcfe7673787b4bfea2c213df443d312aa754757b ("net: dsa: tag_sja1105:
absorb logic for not overwriting precise info into dsa_8021q_rcv()")
added support to let the DSA switch driver set source_port and
switch_id. tag_8021q's logic overrides the previously set source_port
and switch_id only if they are marked as "invalid" (-1). sja1105 and
vsc73xx drivers are doing that properly, but ocelot_8021q driver doesn't
initialize those variables. That causes dsa_8021q_rcv() doesn't set
them, and they remain unassigned.

Initialize them as invalid to so dsa_8021q_rcv() can return with the
proper values.

Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
Cc: stable@vger.kernel.org
---
 net/dsa/tag_ocelot_8021q.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
index 8e8b1bef6af6..11ea8cfd6266 100644
--- a/net/dsa/tag_ocelot_8021q.c
+++ b/net/dsa/tag_ocelot_8021q.c
@@ -79,7 +79,7 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
 				  struct net_device *netdev)
 {
-	int src_port, switch_id;
+	int src_port = -1, switch_id = -1;
 
 	dsa_8021q_rcv(skb, &src_port, &switch_id, NULL, NULL);
 
-- 
2.43.0

On Wed, Dec 11, 2024 at 01:46:56PM +0100, Robert Hodaszi wrote:
> Commit dcfe7673787b4bfea2c213df443d312aa754757b ("net: dsa: tag_sja1105:
> absorb logic for not overwriting precise info into dsa_8021q_rcv()")
> added support to let the DSA switch driver set source_port and
> switch_id. tag_8021q's logic overrides the previously set source_port
> and switch_id only if they are marked as "invalid" (-1). sja1105 and
> vsc73xx drivers are doing that properly, but ocelot_8021q driver doesn't
> initialize those variables. That causes dsa_8021q_rcv() doesn't set
> them, and they remain unassigned.
> 
> Initialize them as invalid to so dsa_8021q_rcv() can return with the
> proper values.
> 
> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
> Cc: stable@vger.kernel.org
> ---

Thank you for the patch, and sorry for the breakage. I suggest the
following alternative commit message:

  The blamed commit changed the dsa_8021q_rcv() calling convention to
  accept pre-populated source_port and switch_id arguments. If those are
  not available, as in the case of tag_ocelot_8021q, the arguments must
  be preinitialized with -1.

  Due to the bug of passing uninitialized arguments, dsa_8021q_rcv()
  does not detect that it needs to populate the source_port and
  switch_id, and this makes dsa_conduit_find_user() fail, and leads to
  packet loss on reception.

  Fixes: dcfe7673787b ("net: dsa: tag_sja1105: absorb logic for not overwriting precise info into dsa_8021q_rcv()")
  Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
  Cc: stable@vger.kernel.org

2024. 12. 11. 15:37 keltezéssel, Vladimir Oltean írta:
> [EXTERNAL E-MAIL] Warning! This email originated outside of the organization! Do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
>
> On Wed, Dec 11, 2024 at 01:46:56PM +0100, Robert Hodaszi wrote:
>> Commit dcfe7673787b4bfea2c213df443d312aa754757b ("net: dsa: tag_sja1105:
>> absorb logic for not overwriting precise info into dsa_8021q_rcv()")
>> added support to let the DSA switch driver set source_port and
>> switch_id. tag_8021q's logic overrides the previously set source_port
>> and switch_id only if they are marked as "invalid" (-1). sja1105 and
>> vsc73xx drivers are doing that properly, but ocelot_8021q driver doesn't
>> initialize those variables. That causes dsa_8021q_rcv() doesn't set
>> them, and they remain unassigned.
>>
>> Initialize them as invalid to so dsa_8021q_rcv() can return with the
>> proper values.
>>
>> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
>> Cc: stable@vger.kernel.org
>> ---
> Thank you for the patch, and sorry for the breakage. I suggest the
> following alternative commit message:
>
>   The blamed commit changed the dsa_8021q_rcv() calling convention to
>   accept pre-populated source_port and switch_id arguments. If those are
>   not available, as in the case of tag_ocelot_8021q, the arguments must
>   be preinitialized with -1.
>
>   Due to the bug of passing uninitialized arguments, dsa_8021q_rcv()
>   does not detect that it needs to populate the source_port and
>   switch_id, and this makes dsa_conduit_find_user() fail, and leads to
>   packet loss on reception.
>
>   Fixes: dcfe7673787b ("net: dsa: tag_sja1105: absorb logic for not overwriting precise info into dsa_8021q_rcv()")
>   Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
>   Cc: stable@vger.kernel.org

Yes, that commit message makes much more sense than mine. Unfortunately, I already sent out the new patch. I rewrite it, and send out a v2 then.

Robert

On Wed, Dec 11, 2024 at 01:46:56PM +0100, Robert Hodaszi wrote:
> Commit dcfe7673787b4bfea2c213df443d312aa754757b ("net: dsa: tag_sja1105:
> absorb logic for not overwriting precise info into dsa_8021q_rcv()")
> added support to let the DSA switch driver set source_port and
> switch_id. tag_8021q's logic overrides the previously set source_port
> and switch_id only if they are marked as "invalid" (-1). sja1105 and
> vsc73xx drivers are doing that properly, but ocelot_8021q driver doesn't
> initialize those variables. That causes dsa_8021q_rcv() doesn't set
> them, and they remain unassigned.
> 
> Initialize them as invalid to so dsa_8021q_rcv() can return with the
> proper values.

Hi Robert

Since this is a fix, it needs a Fixes: tag. Please also base it on net.

There is more here:

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

	Andrew

2024. 12. 11. 14:34 keltezéssel, Andrew Lunn írta:
> [EXTERNAL E-MAIL] Warning! This email originated outside of the organization! Do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
>
> On Wed, Dec 11, 2024 at 01:46:56PM +0100, Robert Hodaszi wrote:
>> Commit dcfe7673787b4bfea2c213df443d312aa754757b ("net: dsa: tag_sja1105:
>> absorb logic for not overwriting precise info into dsa_8021q_rcv()")
>> added support to let the DSA switch driver set source_port and
>> switch_id. tag_8021q's logic overrides the previously set source_port
>> and switch_id only if they are marked as "invalid" (-1). sja1105 and
>> vsc73xx drivers are doing that properly, but ocelot_8021q driver doesn't
>> initialize those variables. That causes dsa_8021q_rcv() doesn't set
>> them, and they remain unassigned.
>>
>> Initialize them as invalid to so dsa_8021q_rcv() can return with the
>> proper values.
> Hi Robert
>
> Since this is a fix, it needs a Fixes: tag. Please also base it on net.
>
> There is more here:
>
> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.kernel.org%2fdoc%2fhtml%2flatest%2fprocess%2fmaintainer-netdev.html&c=E,1,4wyDgaiEANqhFn2GG0tcaR1j57JQtD08e0Ct4VSwo05Uu1yGRm73RMgwy0gs_ClxX5Mmerf2f6bxOoXZF9G_zKOP4Isr6iVcIkPhTzyMVHt9DNUF0KUfXCE,&typo=1
>
>         Andrew

Hi,

OK, thanks! Let me try again!

Robert