[PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[Alok Tiwari]

There is no condition being tested, so it should be netdev_warn,
not netdev_WARN. Using netdev_WARN here is a typo or misuse.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
---
 net/ipv4/udp_tunnel_nic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/udp_tunnel_nic.c b/net/ipv4/udp_tunnel_nic.c
index ff66db48453c..944b3cf25468 100644
--- a/net/ipv4/udp_tunnel_nic.c
+++ b/net/ipv4/udp_tunnel_nic.c
@@ -930,7 +930,7 @@ udp_tunnel_nic_netdevice_event(struct notifier_block *unused,
 
 		err = udp_tunnel_nic_register(dev);
 		if (err)
-			netdev_WARN(dev, "failed to register for UDP tunnel offloads: %d", err);
+			netdev_warn(dev, "failed to register for UDP tunnel offloads: %d", err);
 		return notifier_from_errno(err);
 	}
 	/* All other events will need the udp_tunnel_nic state */
-- 
2.50.1

Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[Simon Horman]

On Wed, Sep 03, 2025 at 12:57:12PM -0700, Alok Tiwari wrote:
> There is no condition being tested, so it should be netdev_warn,
> not netdev_WARN. Using netdev_WARN here is a typo or misuse.

Hi Alok,

I agree that using netdev_warn() seems more appropriate.

But doesn't the difference between netdev_warn() and netdev_WARN()
lie in the output they produce rather than testing of a condition
(or not)?

> 
> Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>

...

Re: [External] : Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[ALOK TIWARI]

On 9/4/2025 2:48 PM, Simon Horman wrote:
> On Wed, Sep 03, 2025 at 12:57:12PM -0700, Alok Tiwari wrote:
>> There is no condition being tested, so it should be netdev_warn,
>> not netdev_WARN. Using netdev_WARN here is a typo or misuse.
> 
> Hi Alok,
> 
> I agree that using netdev_warn() seems more appropriate.
> 
> But doesn't the difference between netdev_warn() and netdev_WARN()
> lie in the output they produce rather than testing of a condition
> (or not)?
> 
>>
>> Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
> 
> ...

Thanks Simon, agreed, I understand your point.

since WARN() triggers backtrace and dumps the file name
it is not require here. The failure in udp_tunnel_nic_register()
should just be treated as an expected operation failure, not as a kernel bug

Should I send a v2 with an updated commit message
(remove "condition being tested"), or drop these changes?”


Thanks for your review.

Thanks,
Alok

Re: [External] : Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[Jakub Kicinski]

On Thu, 4 Sep 2025 19:15:57 +0530 ALOK TIWARI wrote:
> since WARN() triggers backtrace and dumps the file name
> it is not require here. The failure in udp_tunnel_nic_register()
> should just be treated as an expected operation failure, not as a kernel bug

You keep saying that without really explaining why.
I can make a guess, but the motivation should really be part of 
the commit msg.

Re: [External] : Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[ALOK TIWARI]

On 9/4/2025 7:58 PM, Jakub Kicinski wrote:
> On Thu, 4 Sep 2025 19:15:57 +0530 ALOK TIWARI wrote:
>> since WARN() triggers backtrace and dumps the file name
>> it is not require here. The failure in udp_tunnel_nic_register()
>> should just be treated as an expected operation failure, not as a kernel bug
> 
> You keep saying that without really explaining why.
> I can make a guess, but the motivation should really be part of
> the commit msg.


Thanks Jakub.

Thanks for pointing that out.

I was referring to the comment in include/linux/netdevice.h
which notes that netdev_WARN() uses WARN/WARN_ON to print
a backtrace along with file/line information.

In this case, udp_tunnel_nic_register() returning an error is
just a failed operation, not a kernel bug. So a simple warning
message is appropriate, and netdev_warn() should be used
instead of netdev_WARN().
That is my understanding here.

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/include/linux/netdevice.h#n5525

Thanks,
Alok

Re: [External] : Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[Jakub Kicinski]

On Thu, 4 Sep 2025 20:11:36 +0530 ALOK TIWARI wrote:
> In this case, udp_tunnel_nic_register() returning an error is
> just a failed operation, not a kernel bug. So a simple warning
> message is appropriate, and netdev_warn() should be used
> instead of netdev_WARN().

The distinction should be that WARN is only used in cases which
author of the code expects never to occur.

Re: [External] : Re: [PATCH net-next] udp_tunnel: Fix typo using netdev_WARN instead of netdev_warn

[Simon Horman]

On Thu, Sep 04, 2025 at 07:15:57PM +0530, ALOK TIWARI wrote:
> 
> 
> On 9/4/2025 2:48 PM, Simon Horman wrote:
> > On Wed, Sep 03, 2025 at 12:57:12PM -0700, Alok Tiwari wrote:
> > > There is no condition being tested, so it should be netdev_warn,
> > > not netdev_WARN. Using netdev_WARN here is a typo or misuse.
> > 
> > Hi Alok,
> > 
> > I agree that using netdev_warn() seems more appropriate.
> > 
> > But doesn't the difference between netdev_warn() and netdev_WARN()
> > lie in the output they produce rather than testing of a condition
> > (or not)?
> > 
> > > 
> > > Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
> > 
> > ...
> 
> Thanks Simon, agreed, I understand your point.
> 
> since WARN() triggers backtrace and dumps the file name
> it is not require here. The failure in udp_tunnel_nic_register()
> should just be treated as an expected operation failure, not as a kernel bug
> 
> Should I send a v2 with an updated commit message
> (remove "condition being tested"), or drop these changes?”
> 
> 
> Thanks for your review.

Thanks Alok,

I think the change itself is good.
And I'd resubmit with an updated commit message.