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Commit b2aa2c4e authored by Jessica Zhang's avatar Jessica Zhang Committed by Greg Kroah-Hartman
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drm/msm/mdp5: Return error code in mdp5_pipe_release when deadlock is detected 



[ Upstream commit d59be579fa932c46b908f37509f319cbd4ca9a68 ]

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: default avatarTomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: default avatarJessica Zhang <quic_jesszhan@quicinc.com>
Fixes: 7907a0d7 ("drm/msm/mdp5: Use the new private_obj state")
Reviewed-by: default avatarRob Clark <robdclark@gmail.com>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/485179/
Link: https://lore.kernel.org/r/20220505214051.155-1-quic_jesszhan@quicinc.com


Signed-off-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent cd4cfd99

drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c

+11 −4
Original line number Diff line number Diff line
@@ -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)

drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c

+16 −4
Original line number Diff line number Diff line
@@ -393,12 +393,24 @@ 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;

	}