Re: [RFC PATCH 1/3] workqueue: Add an interface to taint workqueue lockdep with reclaim

[Tejun Heo <tj@kernel.org>]

Hello,

On Tue, Oct 21, 2025 at 03:04:14PM -0700, Matthew Brost wrote:
> > Hmm... would it make sense to tie this to WQ_MEM_RECLAIM - ie. enable it
> > implicitly on workqueues w/ the flag set?
> 
> I had considered this, and for a while I thought WQ_MEM_RECLAIM already
> did what I'm suggesting—especially since I’ve spotted bugs in drivers
> where I would have expected lockdep to catch them.
> 
> In my opinion, this approach is better, but it has a broader kernel-wide
> scope and could potentially break some things. My subsequent patches
> will likely break one or two DRM drivers, so it might not be a concern
> to fix everything that breaks across the kernel. It's up to you which
> route we want to take here.

Yeah, it is bothersome that WQ_MEM_RECLAIM doesn't currently have a way to
ensure compliance. I just didn't know about the lockdep mechanism. Can you
please update the patch so that WQ_MEM_RECLAIM implicitly enables the
checking?

Thanks.

-- 
tejun