Re: [PATCH net] bridge: mrp: reject zero test interval to avoid OOM panic

On 28/03/2026 02:19, Jakub Kicinski wrote:
> On Fri, 27 Mar 2026 13:46:39 +0200 Nikolay Aleksandrov wrote:
>> On 27/03/2026 13:34, Simon Horman wrote:
>>> On Wed, Mar 25, 2026 at 08:24:38PM -0700, Xiang Mei wrote:
>>>> br_mrp_start_test() and br_mrp_start_in_test() accept the user-supplied
>>>> interval value from netlink without validation. When interval is 0,
>>>> usecs_to_jiffies(0) yields 0, causing the delayed work
>>>> (br_mrp_test_work_expired / br_mrp_in_test_work_expired) to reschedule
>>>> itself with zero delay. This creates a tight loop on system_percpu_wq
>>>> that allocates and transmits MRP test frames at maximum rate, exhausting
>>>> all system memory and causing a kernel panic via OOM deadlock.
>>>
>>> I would suspect the primary outcome of this problem is high CPU consumption
>>> rather than memory exhaustion. Is there a reason to expect that
>>> the transmitted fames can't be consumed as fast as they are created?
>>
>> +1
>> More so with CAP_NET_ADMIN you can cause all sorts of OOM and high-cpu usage
>> conditions. This is a configuration error and OOM doesn't lead to panic unless
>> instructed to. I don't think this is worth changing at all.
> 
> Then again if there's no practical use for 0 we should consider
> the risk of getting this sort of submission over and over again?
> Dunno..

Sure, I'm fine either way. To that end the patch looks good, just need the
fixes tag as mentioned earlier.