drm/msm/mdp5: Return error code in mdp5_mixer_release when deadlock is detected

There is a possibility for mdp5_get_global_state to return
-EDEADLK when acquiring the modeset lock, but currently global_state in
mdp5_mixer_release doesn't check for if an error is returned.

To avoid a NULL dereference error, let's have mdp5_mixer_release
check if an error is returned and propagate that error.

Reported-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Fixes: 7907a0d77cb4 ("drm/msm/mdp5: Use the new private_obj state")
Reviewed-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/485181/
Link: https://lore.kernel.org/r/20220505214051.155-2-quic_jesszhan@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
index b966cd69f99dd93093c5ed3ffb14bdc50d2f6e64..fe2922c8d21bf351f51f2be5a255a46e05852dc0 100644 (file)
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
@@ -612,9 +612,15 @@ static int mdp5_crtc_setup_pipeline(struct drm_crtc *crtc,
                if (ret)
                        return ret;
 
-               mdp5_mixer_release(new_crtc_state->state, old_mixer);
+               ret = mdp5_mixer_release(new_crtc_state->state, old_mixer);
+               if (ret)
+                       return ret;
+
                if (old_r_mixer) {
-                       mdp5_mixer_release(new_crtc_state->state, old_r_mixer);
+                       ret = mdp5_mixer_release(new_crtc_state->state, old_r_mixer);
+                       if (ret)
+                               return ret;
+
                        if (!need_right_mixer)
                                pipeline->r_mixer = NULL;
                }

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.c
index 954db683ae4444f1486bb1979e976dd797074604..2536def2a0005df9fc3bba450c8bf28582d4a16d 100644 (file)
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.c
@@ -116,21 +116,28 @@ int mdp5_mixer_assign(struct drm_atomic_state *s, struct drm_crtc *crtc,
        return 0;
 }
 
-void mdp5_mixer_release(struct drm_atomic_state *s, struct mdp5_hw_mixer *mixer)
+int mdp5_mixer_release(struct drm_atomic_state *s, struct mdp5_hw_mixer *mixer)
 {
        struct mdp5_global_state *global_state = mdp5_get_global_state(s);
-       struct mdp5_hw_mixer_state *new_state = &global_state->hwmixer;
+       struct mdp5_hw_mixer_state *new_state;
 
        if (!mixer)
-               return;
+               return 0;
+
+       if (IS_ERR(global_state))
+               return PTR_ERR(global_state);
+
+       new_state = &global_state->hwmixer;
 
        if (WARN_ON(!new_state->hwmixer_to_crtc[mixer->idx]))
-               return;
+               return -EINVAL;
 
        DBG("%s: release from crtc %s", mixer->name,
            new_state->hwmixer_to_crtc[mixer->idx]->name);
 
        new_state->hwmixer_to_crtc[mixer->idx] = NULL;
+
+       return 0;
 }
 
 void mdp5_mixer_destroy(struct mdp5_hw_mixer *mixer)

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.h b/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.h
index 43c9ba43ce18530a3432c2f3cb7c0316f5ad7349..545ee223b9d74077d58bd2d665c3bd0fcfb16d44 100644 (file)
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.h
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.h
@@ -30,7 +30,7 @@ void mdp5_mixer_destroy(struct mdp5_hw_mixer *lm);
 int mdp5_mixer_assign(struct drm_atomic_state *s, struct drm_crtc *crtc,
                      uint32_t caps, struct mdp5_hw_mixer **mixer,
                      struct mdp5_hw_mixer **r_mixer);
-void mdp5_mixer_release(struct drm_atomic_state *s,
-                       struct mdp5_hw_mixer *mixer);
+int mdp5_mixer_release(struct drm_atomic_state *s,
+                      struct mdp5_hw_mixer *mixer);
 
 #endif /* __MDP5_LM_H__ */