On 5/5/2022 1:48 AM, Dmitry Baryshkov wrote:
On Thu, 5 May 2022 at 05:06, Rob Clark <robdclark@xxxxxxxxx> wrote:
On Wed, May 4, 2022 at 6:55 PM Jessica Zhang <quic_jesszhan@xxxxxxxxxxx> wrote:
mdp5_get_global_state runs the risk of hitting a -EDEADLK when acquiring
the modeset lock, but currently mdp5_pipe_release doesn't check for if
an error is returned. Because of this, there is a possibility of
mdp5_pipe_release hitting a NULL dereference error.
To avoid this, let's have mdp5_pipe_release check if
mdp5_get_global_state returns an error and propogate that error.
Changes since v1:
- Separated declaration and initialization of *new_state to avoid
compiler warning
- Fixed some spelling mistakes in commit message
Note that mdp5_mixer_release() needs the same treatment.. one more comment below
Got it, will submit a fix for that.
Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c | 15 +++++++++++----
drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h | 2 +-
drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 20 ++++++++++++++++----
3 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c
index ba6695963aa6..97887a2be082 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c
@@ -119,18 +119,23 @@ int mdp5_pipe_assign(struct drm_atomic_state *s, struct drm_plane *plane,
return 0;
}
-void mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe)
+int mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe)
{
struct msm_drm_private *priv = s->dev->dev_private;
struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
struct mdp5_global_state *state = mdp5_get_global_state(s);
- struct mdp5_hw_pipe_state *new_state = &state->hwpipe;
+ struct mdp5_hw_pipe_state *new_state;
if (!hwpipe)
- return;
+ return -EINVAL;
At least per the current code, !hwpipe is "normal".. I think that fits
the model of things like kfree(NULL), so lets make this just return 0
Especially since we release the r_hwpipe w/o additional check. And
r_hwpipe frequently is NULL.
Noted.
Thanks,
Jessica Zhang
+
+ if (IS_ERR(state))
+ return PTR_ERR(state);
+
+ new_state = &state->hwpipe;
if (WARN_ON(!new_state->hwpipe_to_plane[hwpipe->idx]))
- return;
+ return -EINVAL;
DBG("%s: release from plane %s", hwpipe->name,
new_state->hwpipe_to_plane[hwpipe->idx]->name);
@@ -141,6 +146,8 @@ void mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe)
}
new_state->hwpipe_to_plane[hwpipe->idx] = NULL;
+
+ return 0;
}
void mdp5_pipe_destroy(struct mdp5_hw_pipe *hwpipe)
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h b/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h
index 9b26d0761bd4..cca67938cab2 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h
@@ -37,7 +37,7 @@ int mdp5_pipe_assign(struct drm_atomic_state *s, struct drm_plane *plane,
uint32_t caps, uint32_t blkcfg,
struct mdp5_hw_pipe **hwpipe,
struct mdp5_hw_pipe **r_hwpipe);
-void mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe);
+int mdp5_pipe_release(struct drm_atomic_state *s, struct mdp5_hw_pipe *hwpipe);
struct mdp5_hw_pipe *mdp5_pipe_init(enum mdp5_pipe pipe,
uint32_t reg_offset, uint32_t caps);
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
index 228b22830970..979458482841 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
@@ -311,12 +311,24 @@ static int mdp5_plane_atomic_check_with_state(struct drm_crtc_state *crtc_state,
mdp5_state->r_hwpipe = NULL;
- mdp5_pipe_release(state->state, old_hwpipe);
- mdp5_pipe_release(state->state, old_right_hwpipe);
+ ret = mdp5_pipe_release(state->state, old_hwpipe);
+ if (ret)
+ return ret;
+
+ ret = mdp5_pipe_release(state->state, old_right_hwpipe);
+ if (ret)
+ return ret;
+
}
} else {
- mdp5_pipe_release(state->state, mdp5_state->hwpipe);
- mdp5_pipe_release(state->state, mdp5_state->r_hwpipe);
+ ret = mdp5_pipe_release(state->state, mdp5_state->hwpipe);
+ if (ret)
+ return ret;
+
+ ret = mdp5_pipe_release(state->state, mdp5_state->r_hwpipe);
+ if (ret)
+ return ret;
+
mdp5_state->hwpipe = mdp5_state->r_hwpipe = NULL;
}
--
2.35.1
--
With best wishes
Dmitry
