Re: Please add 2dce224f469f ("netns: protect netns ID lookups with RCU") to LTS

From: Haakon Bugge
Date: Tue Sep 14 2021 - 04:58:15 EST




> On 13 Sep 2021, at 10:42, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Sep 10, 2021 at 02:22:32PM +0000, Haakon Bugge wrote:
>>
>>
>>> On 9 Sep 2021, at 15:30, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>> On Thu, Sep 09, 2021 at 01:10:05PM +0000, Haakon Bugge wrote:
>>>> Hi Greg & Sasha,
>>>>
>>>>
>>>> tl;dr: Please add 2dce224f469f ("netns: protect netns ID lookups with
>>>> RCU") to the stable releases from v5.4 and older. It fixes a
>>>> spin_unlock_bh() in peernet2id() called with IRQs off. I think this
>>>> neat side-effect of commit 2dce224f469f was quite un-intentional,
>>>> hence no Fixes: tag or CC: stable.
>>>
>>> Please provide a working backport for all of the relevant kernel
>>> verisons, as it does not apply cleanly on it's own.
>>
>> I've done the backports. 4.9 is actually not needed, because it uses spin_{lock,unlock}_irqsave() in peernet2id(). Hence, we have an "offending" commit which this one fixes:
>>
>> fba143c66abb ("netns: avoid disabling irq for netns id")
>>
>> Will get'm out during the weekend.
>
> All now queued up, thanks.

Thanks for helping me out here, Greg!


Appreciated, Håkon

>
> greg k-h