Re: [Intel-wired-lan] [PATCH net v2 1/2] i40e: drop udp_tunnel_get_rx_info() call from i40e_open()

[mohammad heib <mheib@redhat.com>]

HI Paolo,
Thank you for the review.

On 12/28/25 11:29 AM, Paolo Abeni wrote:
> On 12/18/25 1:13 PM, mheib@redhat.com wrote:
>> From: Mohammad Heib <mheib@redhat.com>
>>
>> The i40e driver calls udp_tunnel_get_rx_info() during i40e_open().
>> This is redundant because UDP tunnel RX offload state is preserved
>> across device down/up cycles. The udp_tunnel core handles
>> synchronization automatically when required.
>>
>> Furthermore, recent changes in the udp_tunnel infrastructure require
>> querying RX info while holding the udp_tunnel lock. Calling it
>> directly from the ndo_open path violates this requirement,
>> triggering the following lockdep warning:
>>
>>    Call Trace:
>>     <TASK>
>>     ? __udp_tunnel_nic_assert_locked+0x39/0x40 [udp_tunnel]
>>     i40e_open+0x135/0x14f [i40e]
>>     __dev_open+0x121/0x2e0
>>     __dev_change_flags+0x227/0x270
>>     dev_change_flags+0x3d/0xb0
>>     devinet_ioctl+0x56f/0x860
>>     sock_do_ioctl+0x7b/0x130
>>     __x64_sys_ioctl+0x91/0xd0
>>     do_syscall_64+0x90/0x170
>>     ...
>>     </TASK>
>>
>> Remove the redundant and unsafe call to udp_tunnel_get_rx_info() from
>> i40e_open() resolve the locking violation.
>>
>> Fixes: 06a5f7f167c5 ("i40e: Move all UDP port notifiers to single function")
>> Signed-off-by: Mohammad Heib <mheib@redhat.com>
>> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> 
> @Tony: I assume you prefer to take this series into your tree first.
> 
> @Mohammad: I think we don't need to packport this path in old kernels; I
> guess a better fixes tag should point to the recent udp_tunnel
> infrastructure changes.

indeed we don't need this change in the old versions.
I updated the fixes tag to:
   - Fixes: 1ead7501094c ("udp_tunnel: remove rtnl_lock dependency").
This better reflects the change that exposed the problem, even though 
the fix itself is in the driver.


> 
> Thanks,
> 
> Paolo
> 
Thanks,