On Wed, May 4, 2022 at 6:55 PM Jessica Zhang quic_jesszhan@quicinc.com 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
Signed-off-by: Jessica Zhang quic_jesszhan@quicinc.com
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
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