| Message ID | 20190605194556.16744-1-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry | expand |
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 <rodrigosiqueiramelo@gmail.com> > Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> > Cc: Emil Velikov <emil.velikov@collabora.com> > Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > 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 = &crtc->crc; > struct drm_crtc_crc_entry *entry; > int head, tail; > + unsigned long flags; > > - spin_lock(&crc->lock); > + spin_lock_irqsave(&crc->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(&crc->lock); > + spin_unlock_irqrestore(&crc->lock, flags); > > wake_up_interruptible(&crc->wq); > > -- > 2.20.1 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
Le jeu. 6 juin 2019 à 10:12, Ville Syrjälä <ville.syrjala@linux.intel.com> 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 <rodrigosiqueiramelo@gmail.com> > > Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> > > Cc: Emil Velikov <emil.velikov@collabora.com> > > Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> > > > --- > > 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 = &crtc->crc; > > struct drm_crtc_crc_entry *entry; > > int head, tail; > > + unsigned long flags; > > > > - spin_lock(&crc->lock); > > + spin_lock_irqsave(&crc->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(&crc->lock); > > + spin_unlock_irqrestore(&crc->lock, flags); > > > > wake_up_interruptible(&crc->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
On Thu, Jun 06, 2019 at 10:27:23AM +0200, Benjamin Gaignard wrote: > Le jeu. 6 juin 2019 à 10:12, Ville Syrjälä > <ville.syrjala@linux.intel.com> 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 <rodrigosiqueiramelo@gmail.com> > > > Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> > > > Cc: Emil Velikov <emil.velikov@collabora.com> > > > Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> > > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > > > > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> 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 = &crtc->crc; > > > struct drm_crtc_crc_entry *entry; > > > int head, tail; > > > + unsigned long flags; > > > > > > - spin_lock(&crc->lock); > > > + spin_lock_irqsave(&crc->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(&crc->lock); > > > + spin_unlock_irqrestore(&crc->lock, flags); > > > > > > wake_up_interruptible(&crc->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
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 = &crtc->crc; struct drm_crtc_crc_entry *entry; int head, tail; + unsigned long flags; - spin_lock(&crc->lock); + spin_lock_irqsave(&crc->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(&crc->lock); + spin_unlock_irqrestore(&crc->lock, flags); wake_up_interruptible(&crc->wq);
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 <rodrigosiqueiramelo@gmail.com> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Cc: Emil Velikov <emil.velikov@collabora.com> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> --- drivers/gpu/drm/drm_debugfs_crc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)