Re: [PATCH net v3] bridge: cfm: reject invalid CCM interval at configuration time

On 09/06/2026 09:51, Xiang Mei wrote:
> Thanks for your review and the tip. V4 was sent.
> 
> Xiang
> 

Please don't top post on netdev@.

Cheers,
  Nik

> On Mon, Jun 8, 2026 at 11:46 PM Ido Schimmel <[email protected]> wrote:
>>
>> On Sat, Jun 06, 2026 at 02:58:48PM -0700, Xiang Mei wrote:
>>> ccm_tx_work_expired() re-arms itself via queue_delayed_work() using
>>> the configured exp_interval converted by interval_to_us(). When
>>> exp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range,
>>> interval_to_us() returns 0, causing the worker to fire immediately in
>>> a tight loop that allocates skbs until OOM.
>>>
>>> Fix this by validating exp_interval at configuration time:
>>>
>>>   - Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range
>>>     [BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the
>>>     netlink policy so userspace cannot set an invalid value.
>>>
>>>   - Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has
>>>     not yet been configured (defaults to 0 from kzalloc).
>>>
>>> Fixes: 2be665c3940d ("bridge: cfm: Netlink SET configuration Interface.")
>>> Reported-by: Weiming Shi <[email protected]>
>>> Suggested-by: Ido Schimmel <[email protected]>
>>> Signed-off-by: Xiang Mei <[email protected]>
>>
>> Reviewed-by: Ido Schimmel <[email protected]>
>>
>> Nit: I don't think that the Suggested-by is appropriate here since I
>> merely had minor comments on the previous version.