[PATCH AUTOSEL 6.11 192/244] drm/amd/display: Fix possible overflow in integer multiplication

Sasha Levin sashal at kernel.org
Wed Sep 25 11:26:53 UTC 2024


From: Alex Hung <alex.hung at amd.com>

[ Upstream commit 3f96f545f877ac59d0c967f52d760b4b2b3b9a47 ]

[WHAT & HOW]
Integer multiplies integer may overflow in context that expects an
expression of unsigned long long (64 bits). This can be fixed by casting
integer to unsigned long long to force 64 bits results.

This fixes 2 OVERFLOW_BEFORE_WIDEN issues reported by Coverity.

Signed-off-by: Alex Hung <alex.hung at amd.com>
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 .../amd/display/dc/resource/dcn32/dcn32_resource_helpers.c    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
index 47c8a9fbe7546..f5a4e97c40ced 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
@@ -663,7 +663,7 @@ bool dcn32_subvp_drr_admissable(struct dc *dc, struct dc_state *context)
 
 				subvp_disallow |= disallow_subvp_in_active_plus_blank(pipe);
 				refresh_rate = (pipe->stream->timing.pix_clk_100hz * (uint64_t)100 +
-					pipe->stream->timing.v_total * pipe->stream->timing.h_total - (uint64_t)1);
+					pipe->stream->timing.v_total * (unsigned long long)pipe->stream->timing.h_total - (uint64_t)1);
 				refresh_rate = div_u64(refresh_rate, pipe->stream->timing.v_total);
 				refresh_rate = div_u64(refresh_rate, pipe->stream->timing.h_total);
 			}
@@ -724,7 +724,7 @@ bool dcn32_subvp_vblank_admissable(struct dc *dc, struct dc_state *context, int
 
 				subvp_disallow |= disallow_subvp_in_active_plus_blank(pipe);
 				refresh_rate = (pipe->stream->timing.pix_clk_100hz * (uint64_t)100 +
-					pipe->stream->timing.v_total * pipe->stream->timing.h_total - (uint64_t)1);
+					pipe->stream->timing.v_total * (unsigned long long)pipe->stream->timing.h_total - (uint64_t)1);
 				refresh_rate = div_u64(refresh_rate, pipe->stream->timing.v_total);
 				refresh_rate = div_u64(refresh_rate, pipe->stream->timing.h_total);
 			}
-- 
2.43.0



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