Re: linux-next: manual merge of the workqueues tree with the tip tree

From: Sebastian Andrzej Siewior
Date: Mon Nov 18 2019 - 04:00:17 EST

On 2019-11-18 15:08:58 [+1100], Stephen Rothwell wrote:
> Hi all,

> Today's linux-next merge of the workqueues tree got a conflict in:
> kernel/workqueue.c
> between commit:
> 5a6446626d7e ("workqueue: Convert for_each_wq to use built-in list check")
> from the tip tree and commit:
> 49e9d1a9faf2 ("workqueue: Add RCU annotation for pwq list walk")
> from the workqueues tree.

urgh. So the RCU warning is introduced in commit
28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")

which was merged in v5.4-rc1. I enabled it around -rc7 and saw a few
warnings including in the workqueue code. I asked about this and posted
later a patch which was applied by Tejun. Now I see that the tip tree
has a patch for this warningâ
I would vote for the patch in -tip since it also removes the
assert_rcu_or_wq_mutex() macro.
It would be nice if this could be part of v5.4 since once the RCU
warning is enabled it will yell.