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

[Haakon Bugge]

> 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.


Thxs, Håkon