On 06/05/2022 00:40, Jessica Zhang 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
Changes since v2:
- Return 0 in case where hwpipe is NULL as this is considered normal behavior
- Added 2nd patch in series to fix a similar NULL dereference issue in mdp5_mixer_release
Reported-by: Tomeu Vizoso tomeu.vizoso@collabora.com Signed-off-by: Jessica Zhang quic_jesszhan@quicinc.com
Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org
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..a4f5cb90f3e8 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 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; }