Re: [ANNOUNCE] 4.4.229-rt200

From: Sebastian Andrzej Siewior
Date: Thu Jul 09 2020 - 05:31:58 EST


On 2020-07-08 18:44:02 [-0000], Daniel Wagner wrote:
> I'm pleased to announce the 4.4.229-rt200 stable release.
>
> This release is just an update to the new stable 4.4.215 version.

Your template is off here.

> Note: This update required dealing with a conflict in net/core/dev.c, where
> devnet_rename_seq was moved from a seqence count to an RWSEM and renamed
> to devnet_rename_sem. If you encounter runtime issues that show tracebacks
> in net/core/dev.c, please let me know.
>
> Patch "net: Add a mutex around devnet_rename_seq" dropped in favour of
> 602c47fbf46b ("net: core: device_rename: Use rwsem instead of a seqcount")

Yes, this was the intention of the exercise :)

> Known issues:
>
> sigwaittest with hackbench as workload is able to trigger a crash on x86_64,
> the same as reported for the v4.4.220-rt196 release. The crash seems to
> be triggered by a BPF program. IIRC, BPF was never supported in v4.4-rt
> and I just forgot to disable in my configuration.

In v5.4.3-rt1 there is
fe18e9e08e25d ("BPF: Disable on PREEMPT_RT")

so maybe backport this across the stable kernels. Fixing it is a way
larger queue. If the intention is to keep it disabled it could be
enforced via Kconfig so it is not enabled by accident (or by using
oldconfig on a distro config which has it enabled).

> Enjoy!
> Daniel

Sebastian