From d59be579fa932c46b908f37509f319cbd4ca9a68 Mon Sep 17 00:00:00 2001 From: Jessica Zhang Date: Thu, 5 May 2022 14:40:50 -0700 Subject: drm/msm/mdp5: Return error code in mdp5_pipe_release when deadlock is detected 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 Signed-off-by: Jessica Zhang Fixes: 7907a0d77cb4 ("drm/msm/mdp5: Use the new private_obj state") Reviewed-by: Rob Clark Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/485179/ Link: https://lore.kernel.org/r/20220505214051.155-1-quic_jesszhan@quicinc.com Signed-off-by: Dmitry Baryshkov --- 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; } -- cgit