Re: [PATCH] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry
On Thu, Jun 06, 2019 at 10:27:23AM +0200, Benjamin Gaignard wrote:
> Le jeu. 6 juin 2019 à 10:12, Ville Syrjälä
> a écrit :
> >
> > On Wed, Jun 05, 2019 at 09:45:56PM +0200, Daniel Vetter wrote:
> > > We can be called from any context, we need to be prepared.
> > >
> > > Noticed this while hacking on vkms, which calls this function from a
> > > normal worker. Which really upsets lockdep.
> > >
> > > Cc: Rodrigo Siqueira
> > > Cc: Tomeu Vizoso
> > > Cc: Emil Velikov
> > > Cc: Benjamin Gaignard
> > > Signed-off-by: Daniel Vetter
> >
> > Reviewed-by: Ville Syrjälä
>
> Reviewed-by: Benjamin Gaignard
Thanks for taking a look, patch pushed to drm-misc-next.
-Daniel
>
> >
> > > ---
> > > drivers/gpu/drm/drm_debugfs_crc.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_debugfs_crc.c
> > > b/drivers/gpu/drm/drm_debugfs_crc.c
> > > index 585169f0dcc5..7f35b5ba1924 100644
> > > --- a/drivers/gpu/drm/drm_debugfs_crc.c
> > > +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> > > @@ -396,8 +396,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc,
> > > bool has_frame,
> > > struct drm_crtc_crc *crc = >crc;
> > > struct drm_crtc_crc_entry *entry;
> > > int head, tail;
> > > + unsigned long flags;
> > >
> > > - spin_lock(>lock);
> > > + spin_lock_irqsave(>lock, flags);
> > >
> > > /* Caller may not have noticed yet that userspace has stopped
> > > reading */
> > > if (!crc->entries) {
> > > @@ -428,7 +429,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc,
> > > bool has_frame,
> > > head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
> > > crc->head = head;
> > >
> > > - spin_unlock(>lock);
> > > + spin_unlock_irqrestore(>lock, flags);
> > >
> > > wake_up_interruptible(>wq);
> > >
> > > --
> > > 2.20.1
> > >
> > > ___
> > > dri-devel mailing list
> > > dri-devel@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >
> > --
> > Ville Syrjälä
> > Intel
> > ___
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry
Le jeu. 6 juin 2019 à 10:12, Ville Syrjälä
a écrit :
>
> On Wed, Jun 05, 2019 at 09:45:56PM +0200, Daniel Vetter wrote:
> > We can be called from any context, we need to be prepared.
> >
> > Noticed this while hacking on vkms, which calls this function from a
> > normal worker. Which really upsets lockdep.
> >
> > Cc: Rodrigo Siqueira
> > Cc: Tomeu Vizoso
> > Cc: Emil Velikov
> > Cc: Benjamin Gaignard
> > Signed-off-by: Daniel Vetter
>
> Reviewed-by: Ville Syrjälä
Reviewed-by: Benjamin Gaignard
>
> > ---
> > drivers/gpu/drm/drm_debugfs_crc.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_debugfs_crc.c
> > b/drivers/gpu/drm/drm_debugfs_crc.c
> > index 585169f0dcc5..7f35b5ba1924 100644
> > --- a/drivers/gpu/drm/drm_debugfs_crc.c
> > +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> > @@ -396,8 +396,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool
> > has_frame,
> > struct drm_crtc_crc *crc = >crc;
> > struct drm_crtc_crc_entry *entry;
> > int head, tail;
> > + unsigned long flags;
> >
> > - spin_lock(>lock);
> > + spin_lock_irqsave(>lock, flags);
> >
> > /* Caller may not have noticed yet that userspace has stopped reading
> > */
> > if (!crc->entries) {
> > @@ -428,7 +429,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool
> > has_frame,
> > head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
> > crc->head = head;
> >
> > - spin_unlock(>lock);
> > + spin_unlock_irqrestore(>lock, flags);
> >
> > wake_up_interruptible(>wq);
> >
> > --
> > 2.20.1
> >
> > ___
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Ville Syrjälä
> Intel
> ___
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
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Re: [PATCH] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry
On Wed, Jun 05, 2019 at 09:45:56PM +0200, Daniel Vetter wrote:
> We can be called from any context, we need to be prepared.
>
> Noticed this while hacking on vkms, which calls this function from a
> normal worker. Which really upsets lockdep.
>
> Cc: Rodrigo Siqueira
> Cc: Tomeu Vizoso
> Cc: Emil Velikov
> Cc: Benjamin Gaignard
> Signed-off-by: Daniel Vetter
Reviewed-by: Ville Syrjälä
> ---
> drivers/gpu/drm/drm_debugfs_crc.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_debugfs_crc.c
> b/drivers/gpu/drm/drm_debugfs_crc.c
> index 585169f0dcc5..7f35b5ba1924 100644
> --- a/drivers/gpu/drm/drm_debugfs_crc.c
> +++ b/drivers/gpu/drm/drm_debugfs_crc.c
> @@ -396,8 +396,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool
> has_frame,
> struct drm_crtc_crc *crc = >crc;
> struct drm_crtc_crc_entry *entry;
> int head, tail;
> + unsigned long flags;
>
> - spin_lock(>lock);
> + spin_lock_irqsave(>lock, flags);
>
> /* Caller may not have noticed yet that userspace has stopped reading */
> if (!crc->entries) {
> @@ -428,7 +429,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool
> has_frame,
> head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
> crc->head = head;
>
> - spin_unlock(>lock);
> + spin_unlock_irqrestore(>lock, flags);
>
> wake_up_interruptible(>wq);
>
> --
> 2.20.1
>
> ___
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel
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