2021-03-20 13:39:38

by Dmitry Vyukov

Subject: [PATCH] drm/vkms: fix misuse of WARN_ON

vkms_vblank_simulate() uses WARN_ON for timing-dependent condition
(timer overrun). This is a mis-use of WARN_ON, WARN_ON must be used
to denote kernel bugs. Use pr_warn() instead.

Signed-off-by: Dmitry Vyukov <[email protected]>
Reported-by: [email protected]
Cc: Rodrigo Siqueira <[email protected]>
Cc: Melissa Wen <[email protected]>
Cc: Haneen Mohammed <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: David Airlie <[email protected]>
Cc: [email protected]
Cc: [email protected]
Change-Id: I7f01c288092bc7e472ec63af198f93ce3d8c49f7
---
drivers/gpu/drm/vkms/vkms_crtc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 0443b7deeaef6..758d8a98d96b3 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -18,7 +18,8 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)

ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
output->period_ns);
- WARN_ON(ret_overrun != 1);
+ if (ret_overrun != 1)
+ pr_warn("%s: vblank timer overrun\n", __func__);

spin_lock(&output->lock);
ret = drm_crtc_handle_vblank(crtc);

base-commit: e94c55b8e0a0bbe9a026250cf31e2fa45957d776
--
2.31.0.291.g576ba9dcdaf-goog

2021-03-25 03:32:36

by Melissa Wen

Subject: Re: [PATCH] drm/vkms: fix misuse of WARN_ON

On 03/20, Dmitry Vyukov wrote:
> vkms_vblank_simulate() uses WARN_ON for timing-dependent condition
> (timer overrun). This is a mis-use of WARN_ON, WARN_ON must be used
> to denote kernel bugs. Use pr_warn() instead.
>
> Signed-off-by: Dmitry Vyukov <[email protected]>
> Reported-by: [email protected]
> Cc: Rodrigo Siqueira <[email protected]>
> Cc: Melissa Wen <[email protected]>
> Cc: Haneen Mohammed <[email protected]>
> Cc: Daniel Vetter <[email protected]>
> Cc: David Airlie <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Change-Id: I7f01c288092bc7e472ec63af198f93ce3d8c49f7
> ---
> drivers/gpu/drm/vkms/vkms_crtc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index 0443b7deeaef6..758d8a98d96b3 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -18,7 +18,8 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
>
> ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
> output->period_ns);
> - WARN_ON(ret_overrun != 1);
> + if (ret_overrun != 1)
> + pr_warn("%s: vblank timer overrun\n", __func__);

Hi Dmitry,

Thanks for your patch.

Looks good to me.
The Change-Id tag just seems a little noisy to me, but can be
fixed while applying.

Acked-by: Melissa Wen <[email protected]>

>
> spin_lock(&output->lock);
> ret = drm_crtc_handle_vblank(crtc);
>
> base-commit: e94c55b8e0a0bbe9a026250cf31e2fa45957d776
> --
> 2.31.0.291.g576ba9dcdaf-goog
>

2021-03-25 06:50:48

by Dmitry Vyukov

Subject: Re: [PATCH] drm/vkms: fix misuse of WARN_ON

On Wed, Mar 24, 2021 at 11:00 PM Melissa Wen <[email protected]> wrote:
>
> On 03/20, Dmitry Vyukov wrote:
> > vkms_vblank_simulate() uses WARN_ON for timing-dependent condition
> > (timer overrun). This is a mis-use of WARN_ON, WARN_ON must be used
> > to denote kernel bugs. Use pr_warn() instead.
> >
> > Signed-off-by: Dmitry Vyukov <[email protected]>
> > Reported-by: [email protected]
> > Cc: Rodrigo Siqueira <[email protected]>
> > Cc: Melissa Wen <[email protected]>
> > Cc: Haneen Mohammed <[email protected]>
> > Cc: Daniel Vetter <[email protected]>
> > Cc: David Airlie <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Change-Id: I7f01c288092bc7e472ec63af198f93ce3d8c49f7
> > ---
> > drivers/gpu/drm/vkms/vkms_crtc.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> > index 0443b7deeaef6..758d8a98d96b3 100644
> > --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> > +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> > @@ -18,7 +18,8 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
> >
> > ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
> > output->period_ns);
> > - WARN_ON(ret_overrun != 1);
> > + if (ret_overrun != 1)
> > + pr_warn("%s: vblank timer overrun\n", __func__);
>
> Hi Dmitry,
>
> Thanks for your patch.
>
> Looks good to me.
> The Change-Id tag just seems a little noisy to me, but can be
> fixed while applying.

Yes, please drop Change-Id when applying if possible. Sorry for that.
Thanks for the review, Melissa.

> Acked-by: Melissa Wen <[email protected]>
>
> >
> > spin_lock(&output->lock);
> > ret = drm_crtc_handle_vblank(crtc);
> >
> > base-commit: e94c55b8e0a0bbe9a026250cf31e2fa45957d776
> > --
> > 2.31.0.291.g576ba9dcdaf-goog
> >

2021-03-25 11:59:39

by Melissa Wen

Subject: Re: [PATCH] drm/vkms: fix misuse of WARN_ON

On 03/25, Dmitry Vyukov wrote:
> On Wed, Mar 24, 2021 at 11:00 PM Melissa Wen <[email protected]> wrote:
> >
> > On 03/20, Dmitry Vyukov wrote:
> > > vkms_vblank_simulate() uses WARN_ON for timing-dependent condition
> > > (timer overrun). This is a mis-use of WARN_ON, WARN_ON must be used
> > > to denote kernel bugs. Use pr_warn() instead.
> > >
> > > Signed-off-by: Dmitry Vyukov <[email protected]>
> > > Reported-by: [email protected]
> > > Cc: Rodrigo Siqueira <[email protected]>
> > > Cc: Melissa Wen <[email protected]>
> > > Cc: Haneen Mohammed <[email protected]>
> > > Cc: Daniel Vetter <[email protected]>
> > > Cc: David Airlie <[email protected]>
> > > Cc: [email protected]
> > > Cc: [email protected]
> > > Change-Id: I7f01c288092bc7e472ec63af198f93ce3d8c49f7
> > > ---
> > > drivers/gpu/drm/vkms/vkms_crtc.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> > > index 0443b7deeaef6..758d8a98d96b3 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> > > @@ -18,7 +18,8 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
> > >
> > > ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
> > > output->period_ns);
> > > - WARN_ON(ret_overrun != 1);
> > > + if (ret_overrun != 1)
> > > + pr_warn("%s: vblank timer overrun\n", __func__);
> >
> > Hi Dmitry,
> >
> > Thanks for your patch.
> >
> > Looks good to me.
> > The Change-Id tag just seems a little noisy to me, but can be
> > fixed while applying.
>
> Yes, please drop Change-Id when applying if possible. Sorry for that.
> Thanks for the review, Melissa.

Applied to drm-misc-next.

Thanks,

Melissa
>
> > Acked-by: Melissa Wen <[email protected]>
> >
> > >
> > > spin_lock(&output->lock);
> > > ret = drm_crtc_handle_vblank(crtc);
> > >
> > > base-commit: e94c55b8e0a0bbe9a026250cf31e2fa45957d776
> > > --
> > > 2.31.0.291.g576ba9dcdaf-goog
> > >