[PATCH 5.17 341/772] drm/msm/mdp5: Return error code in mdp5_mixer_release when deadlock is detected

Greg Kroah-Hartman
2022-06-07T21:08:05Z

From: Jessica Zhang <quic_jesszhan@quicinc.com>

[ Upstream commit ca75f6f7c6f89365e40f10f641b15981b1f07c31 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 10 ++++++++--
drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.c | 15 +++++++++++----
drivers/gpu/drm/msm/disp/mdp5/mdp5_mixer.h | 4 ++--
3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
index bb7d066618e6..477cda4ec23b 100644
--- 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 954db683ae44..2536def2a000 100644
--- 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 43c9ba43ce18..545ee223b9d7 100644
--- 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__ */
--
2.35.1