lkml.org 
[lkml]   [2020]   [Aug]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH][next] drm/amd/display: fix potential integer overflow when shifting 32 bit variable bl_pwm
Date
From: Colin Ian King <colin.king@canonical.com>

The 32 bit unsigned integer bl_pwm is being shifted using 32 bit arithmetic
and then being assigned to a 64 bit unsigned integer. There is a potential
for a 32 bit overflow so cast bl_pwm to enforce a 64 bit shift operation
to avoid this.

Addresses-Coverity: ("unintentional integer overflow")
Fixes: 3ba01817365c ("drm/amd/display: Move panel_cntl specific register from abm to panel_cntl.")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c b/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c
index a6d73d30837c..df7f826eebd8 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c
@@ -76,7 +76,7 @@ static unsigned int dce_get_16_bit_backlight_from_pwm(struct panel_cntl *panel_c
else
bl_pwm &= 0xFFFF;

- current_backlight = bl_pwm << (1 + bl_int_count);
+ current_backlight = (uint64_t)bl_pwm << (1 + bl_int_count);

if (bl_period == 0)
bl_period = 0xFFFF;
--
2.27.0
\
 
 \ /
  Last update: 2020-08-18 14:10    [W:0.025 / U:25.932 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site