From: Chris Wilson <chris@chris-wilson.co.uk>
To: "Daniel Vetter" <daniel@ffwll.ch>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all
Date: Wed, 01 Nov 2017 14:08:37 +0000 [thread overview]
Message-ID: <150954531759.23379.2731301693481220664@mail.alporthouse.com> (raw)
In-Reply-To: <20171031163826.r2cvt3mxtsjcrdpx@phenom.ffwll.local>
Quoting Daniel Vetter (2017-10-31 16:38:26)
> On Tue, Oct 31, 2017 at 03:28:01PM +0200, Ville Syrjälä wrote:
> > On Tue, Oct 31, 2017 at 11:55:35AM +0000, Chris Wilson wrote:
> > > To acquire all modeset locks requires a ww_ctx to be allocated. As this
> > > is the legacy path and the allocation small, to reduce the changes
> > > required (and complex untested error handling) to the legacy drivers, we
> > > simply assume that the allocation succeeds. At present, it relies on the
> > > too-small-to-fail rule, but syzbot found that by injecting a failure
> > > here we would hit the WARN. Document that this allocation must succeed
> > > with __GFP_NOFAIL.
>
> Note that for atomic drivers at least all the core/helper paths are fixed
> up correctly. But e.g. i915 has still plenty of callsites in its own code,
> mostly debugfs.
>
> > > Reported-by: syzbot (syzkaller)
> > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >
> > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Applied, thanks.
Just curious as it hasn't shown up in drm-tip yet, so I'm worrying if it
found a crack to hide in.
-Chris
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next prev parent reply other threads:[~2017-11-01 14:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 11:55 [PATCH] drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all Chris Wilson
2017-10-31 12:31 ` ✗ Fi.CI.BAT: failure for drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all (rev2) Patchwork
2017-10-31 13:12 ` [PATCH] drm: Require __GFP_NOFAIL for the legacy drm_modeset_lock_all Chris Wilson
2017-10-31 13:28 ` Ville Syrjälä
2017-10-31 16:38 ` Daniel Vetter
2017-11-01 14:08 ` Chris Wilson [this message]
2017-11-02 9:42 ` Daniel Vetter
-- strict thread matches above, loose matches on Subject: below --
2017-10-31 11:52 Chris Wilson
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