From: Joshua Aberback <[email protected]>

[ Upstream commit 3a7810c212bcf2f722671dadf4b23ff70a7d23ee ]

[Why]
It's possible to generate more than 50 steps in hwss_build_fast_sequence,
for example with a 6-pipe asic where all pipes are in one MPC chain. This
overflows the block_sequence buffer and corrupts block_sequence_steps,
causing a crash.

[How]
Expand block_sequence to 100 items. A naive upper bound on the possible
number of steps for a 6-pipe asic, ignoring the potential for steps to be
mutually exclusive, is 91 with current code, therefore 100 is sufficient.

Reviewed-by: Alvin Lee <[email protected]>
Signed-off-by: Joshua Aberback <[email protected]>
Signed-off-by: Wayne Lin <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/gpu/drm/amd/display/dc/inc/core_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/inc/core_types.h 
b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
index eaad1260bfd18..4b284ce669ae5 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/core_types.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/core_types.h
@@ -532,7 +532,7 @@ struct dc_state {
         */
        struct bw_context bw_ctx;
 
-       struct block_sequence block_sequence[50];
+       struct block_sequence block_sequence[100];
        unsigned int block_sequence_steps;
        struct dc_dmub_cmd dc_dmub_cmd[10];
        unsigned int dmub_cmd_count;
-- 
2.39.5

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