Re: [PATCH v6 3/3] PM: hibernate: fix spurious GFP mask WARNING in uswsusp path

["Rafael J. Wysocki" <rafael@kernel.org>]

On Sat, Mar 21, 2026 at 11:48 AM YoungJun Park <youngjun.park@lge.com> wrote:
>
> On Fri, Mar 20, 2026 at 07:20:24PM +0100, Rafael J. Wysocki wrote:
> >...
>
> Hi Rafael,
>
> Thanks for the review. Sorry for the back and forth on this one.
> I'm preparing to send the uswsusp GFP mask fix separately as you
> requested (with _nowarn rename and lockdep_assert_held).
>
> Before sending, I wanted to check on the approach. I originally
> found this WARNING while testing uswsusp and thought it was a
> localized issue. But AI review has kept uncovering more cases —
> first SNAPSHOT_FREEZE + snapshot_release(), and now
> dpm_resume_end() when dpm_prepare() fails.

dpm_resume_end() should not be called after a failing dpm_prepare().

Which code path is that?

> More callers than I expected use this defensive restore pattern.
>
> So I'd like your thoughts on the approach:
>
> 1. Introduce pm_restore_gfp_mask_nowarn() and update each caller.
>
> 2. Remove the WARN_ON from pm_restore_gfp_mask() itself, restoring
>    the pre-stacking no-op behavior.
>
> I'm leaning towards option 2. Defensive restores are an established
> pattern in multiple paths, and warning against a legitimate no-op
> seems counterproductive — we'd just be playing whack-a-mole with
> _nowarn conversions as more callers turn up.
>
> What do you think?

Using the _nowarn() wariant would help to annotate code paths where
omitting the warning is legitimate.