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

On 9 Sep 2021, at 15:30, Greg KH [off-list ref] wrote:

On Thu, Sep 09, 2021 at 01:10:05PM +0000, Haakon Bugge wrote:

quoted

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