Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Su Sung Chung , Alex Deucher , Sasha Levin Subject: [PATCH AUTOSEL 4.19 14/57] drm/amd/display: fix bug of accessing invalid memory Date: Sun, 4 Nov 2018 08:51:01 -0500 Message-Id: <20181104135144.88324-14-sashal@kernel.org> In-Reply-To: <20181104135144.88324-1-sashal@kernel.org> References: <20181104135144.88324-1-sashal@kernel.org> List-ID: From: Su Sung Chung [ Upstream commit 43c3ff27a47d83d153c4adc088243ba594582bf5 ] [Why] A loop inside of build_evenly_distributed_points function that traverse through the array of points become an infinite loop when m_GammaUpdates does not get assigned to any value. [How] In DMColor, clear m_gammaIsValid bit just before writting all Zeromem for m_GammaUpdates, to prevent calling build_evenly_distributed_points before m_GammaUpdates gets assigned to some value. Signed-off-by: Su Sung Chung Reviewed-by: Aric Cyr Acked-by: Bhawanpreet Lakha Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/modules/color/color_gamma.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c index bf29733958c3..962900932bee 100644 --- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c +++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c @@ -1069,10 +1069,14 @@ static void build_evenly_distributed_points( struct dividers dividers) { struct gamma_pixel *p = points; - struct gamma_pixel *p_last = p + numberof_points - 1; + struct gamma_pixel *p_last; uint32_t i = 0; + // This function should not gets called with 0 as a parameter + ASSERT(numberof_points > 0); + p_last = p + numberof_points - 1; + do { struct fixed31_32 value = dc_fixpt_from_fraction(i, numberof_points - 1); @@ -1083,7 +1087,7 @@ static void build_evenly_distributed_points( ++p; ++i; - } while (i != numberof_points); + } while (i < numberof_points); p->r = dc_fixpt_div(p_last->r, dividers.divider1); p->g = dc_fixpt_div(p_last->g, dividers.divider1); -- 2.17.1