* [PATCH] drm: Avoid connector reference imbalance on error path
@ 2016-05-06 11:47 Chris Wilson
2016-05-18 10:24 ` Daniel Vetter
0 siblings, 1 reply; 2+ messages in thread
From: Chris Wilson @ 2016-05-06 11:47 UTC (permalink / raw)
To: dri-devel; +Cc: Daniel Vetter, Dave Airlie, Daniel Stone
Whilst looking at the fallout from using connector references for
atomic, I noticed that there is an early return buried in
drm_atomic_set_crtc_for_connector() that if hit could cause us to leak a
reference on the connector.
Fixes: d2307dea14 (drm/atomic: use connector references (v3))
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
---
drivers/gpu/drm/drm_atomic.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 86e89db02ed7..3ff1ed7b33db 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1160,14 +1160,18 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
{
struct drm_crtc_state *crtc_state;
- if (crtc)
- drm_connector_reference(conn_state->connector);
- if (conn_state->crtc && conn_state->crtc != crtc) {
+ if (conn_state->crtc == crtc)
+ return 0;
+
+ if (conn_state->crtc) {
crtc_state = drm_atomic_get_existing_crtc_state(conn_state->state,
conn_state->crtc);
crtc_state->connector_mask &=
~(1 << drm_connector_index(conn_state->connector));
+
+ drm_connector_unreference(conn_state->connector);
+ conn_state->crtc = NULL;
}
if (crtc) {
@@ -1177,18 +1181,16 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
crtc_state->connector_mask |=
1 << drm_connector_index(conn_state->connector);
- }
- if (conn_state->crtc)
- drm_connector_unreference(conn_state->connector);
- conn_state->crtc = crtc;
+ drm_connector_reference(conn_state->connector);
+ conn_state->crtc = crtc;
- if (crtc)
DRM_DEBUG_ATOMIC("Link connector state %p to [CRTC:%d:%s]\n",
conn_state, crtc->base.id, crtc->name);
- else
+ } else {
DRM_DEBUG_ATOMIC("Link connector state %p to [NOCRTC]\n",
conn_state);
+ }
return 0;
}
--
2.8.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] drm: Avoid connector reference imbalance on error path
2016-05-06 11:47 [PATCH] drm: Avoid connector reference imbalance on error path Chris Wilson
@ 2016-05-18 10:24 ` Daniel Vetter
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Vetter @ 2016-05-18 10:24 UTC (permalink / raw)
To: Chris Wilson; +Cc: Daniel Vetter, Daniel Stone, dri-devel, Dave Airlie
On Fri, May 06, 2016 at 12:47:45PM +0100, Chris Wilson wrote:
> Whilst looking at the fallout from using connector references for
> atomic, I noticed that there is an early return buried in
> drm_atomic_set_crtc_for_connector() that if hit could cause us to leak a
> reference on the connector.
>
> Fixes: d2307dea14 (drm/atomic: use connector references (v3))
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Daniel Stone <daniels@collabora.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@redhat.com>
Applied to drm-misc, thanks.
-Daniel
> ---
> drivers/gpu/drm/drm_atomic.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 86e89db02ed7..3ff1ed7b33db 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1160,14 +1160,18 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
> {
> struct drm_crtc_state *crtc_state;
>
> - if (crtc)
> - drm_connector_reference(conn_state->connector);
> - if (conn_state->crtc && conn_state->crtc != crtc) {
> + if (conn_state->crtc == crtc)
> + return 0;
> +
> + if (conn_state->crtc) {
> crtc_state = drm_atomic_get_existing_crtc_state(conn_state->state,
> conn_state->crtc);
>
> crtc_state->connector_mask &=
> ~(1 << drm_connector_index(conn_state->connector));
> +
> + drm_connector_unreference(conn_state->connector);
> + conn_state->crtc = NULL;
> }
>
> if (crtc) {
> @@ -1177,18 +1181,16 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
>
> crtc_state->connector_mask |=
> 1 << drm_connector_index(conn_state->connector);
> - }
>
> - if (conn_state->crtc)
> - drm_connector_unreference(conn_state->connector);
> - conn_state->crtc = crtc;
> + drm_connector_reference(conn_state->connector);
> + conn_state->crtc = crtc;
>
> - if (crtc)
> DRM_DEBUG_ATOMIC("Link connector state %p to [CRTC:%d:%s]\n",
> conn_state, crtc->base.id, crtc->name);
> - else
> + } else {
> DRM_DEBUG_ATOMIC("Link connector state %p to [NOCRTC]\n",
> conn_state);
> + }
>
> return 0;
> }
> --
> 2.8.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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https://lists.freedesktop.org/mailman/listinfo/dri-devel
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