58 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			58 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From 8f73c4a08531d65fc4ce12d9a61deb16a7d601cb Mon Sep 17 00:00:00 2001
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From: Boris Brezillon <boris.brezillon@bootlin.com>
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Date: Thu, 15 Nov 2018 11:58:51 +0100
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Subject: [PATCH 762/773] drm/vc4: Fix NULL pointer dereference in the async
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 update path
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vc4_plane_atomic_async_update() calls vc4_plane_atomic_check()
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which in turn calls vc4_plane_setup_clipping_and_scaling(), and since
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commit 58a6a36fe8e0 ("drm/vc4: Use
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drm_atomic_helper_check_plane_state() to simplify the logic"), this
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function accesses plane_state->state which will be NULL when called
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from the async update path because we're passing the current plane
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state, and plane_state->state has been assigned to NULL in
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drm_atomic_helper_swap_state().
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Pass the new state instead of the current one (the new state has
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->state set to a non-NULL value).
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Fixes: 58a6a36fe8e0 ("drm/vc4: Use drm_atomic_helper_check_plane_state() to simplify the logic")
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Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
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Reviewed-by: Eric Anholt <eric@anholt.net>
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Link: https://patchwork.freedesktop.org/patch/msgid/20181115105852.9844-1-boris.brezillon@bootlin.com
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---
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 drivers/gpu/drm/vc4/vc4_plane.c | 15 +++++++++++++--
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 1 file changed, 13 insertions(+), 2 deletions(-)
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--- a/drivers/gpu/drm/vc4/vc4_plane.c
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+++ b/drivers/gpu/drm/vc4/vc4_plane.c
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@@ -905,7 +905,7 @@ void vc4_plane_async_set_fb(struct drm_p
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 static void vc4_plane_atomic_async_update(struct drm_plane *plane,
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 					  struct drm_plane_state *state)
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 {
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-	struct vc4_plane_state *vc4_state = to_vc4_plane_state(plane->state);
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+	struct vc4_plane_state *vc4_state, *new_vc4_state;
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 	if (plane->state->fb != state->fb) {
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 		vc4_plane_async_set_fb(plane, state->fb);
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@@ -927,7 +927,18 @@ static void vc4_plane_atomic_async_updat
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 	plane->state->src_y = state->src_y;
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 	/* Update the display list based on the new crtc_x/y. */
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-	vc4_plane_atomic_check(plane, plane->state);
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+	vc4_plane_atomic_check(plane, state);
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+
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+	new_vc4_state = to_vc4_plane_state(state);
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+	vc4_state = to_vc4_plane_state(plane->state);
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+
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+	/* Update the current vc4_state pos0, pos2 and ptr0 dlist entries. */
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+	vc4_state->dlist[vc4_state->pos0_offset] =
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+		new_vc4_state->dlist[vc4_state->pos0_offset];
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+	vc4_state->dlist[vc4_state->pos2_offset] =
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+		new_vc4_state->dlist[vc4_state->pos2_offset];
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+	vc4_state->dlist[vc4_state->ptr0_offset] =
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+		new_vc4_state->dlist[vc4_state->ptr0_offset];
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 	/* Note that we can't just call vc4_plane_write_dlist()
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 	 * because that would smash the context data that the HVS is
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