RE: [PATCH] video: exynos: fix build warning and bad pointer deref in dp driver
From: Jingoo Han <hidden>
Date: 2012-04-09 08:46:59
Also in:
lkml
quoted hunk ↗ jump to hunk
-----Original Message----- From: Olof Johansson [mailto:olof@lixom.net] Sent: Monday, April 09, 2012 1:16 PM I'm not 100% sure if the fix for 'adjust_request' is correct, since it's uncertain what the original intent was. But it's so clearly an uninitialized pointer dereference that my resolution seems to make sense. drivers/video/exynos/exynos_dp_core.c: In function 'exynos_dp_set_link_train': drivers/video/exynos/exynos_dp_core.c:521:21: warning: 'adjust_request' may be used uninitialized in this function [-Wuninitialized] drivers/video/exynos/exynos_dp_core.c:481:6: note: 'adjust_request' was declared here drivers/video/exynos/exynos_dp_core.c:529:18: warning: 'reg' may be used uninitialized in this function [-Wuninitialized] drivers/video/exynos/exynos_dp_core.c:395:6: note: 'reg' was declared here Signed-off-by: Olof Johansson <redacted> --- drivers/video/exynos/exynos_dp_core.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-)diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c index 2a4481c..8973e18 100644 --- a/drivers/video/exynos/exynos_dp_core.c +++ b/drivers/video/exynos/exynos_dp_core.c@@ -392,24 +392,19 @@ static unsigned int exynos_dp_get_lane_link_training( struct exynos_dp_device *dp, int lane) { - u32 reg; - switch (lane) { case 0: - reg = exynos_dp_get_lane0_link_training(dp); - break; + return exynos_dp_get_lane0_link_training(dp); case 1: - reg = exynos_dp_get_lane1_link_training(dp); - break; + return exynos_dp_get_lane1_link_training(dp); case 2: - reg = exynos_dp_get_lane2_link_training(dp); - break; + return exynos_dp_get_lane2_link_training(dp); case 3: - reg = exynos_dp_get_lane3_link_training(dp); - break; + return exynos_dp_get_lane3_link_training(dp); }
I don't like multi return.
quoted hunk ↗ jump to hunk
- return reg; + WARN_ON(1); + return 0; } static void exynos_dp_reduce_link_rate(struct exynos_dp_device *dp)@@ -489,13 +484,13 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp) 6, link_status); lane_count = dp->link_train.lane_count; + adjust_request = link_status + (DPCD_ADDR_ADJUST_REQUEST_LANE0_1 + - DPCD_ADDR_LANE0_1_STATUS); +
It makes the problem. adjust_request will be different. OK, I understand what you want to do. I will send the version 2 patch which is simpler. Thank you for sending the patch.
if (exynos_dp_clock_recovery_ok(link_status, lane_count) = 0) {
/* set training pattern 2 for EQ */
exynos_dp_set_training_pattern(dp, TRAINING_PTN2);
- adjust_request = link_status + (DPCD_ADDR_ADJUST_REQUEST_LANE0_1
- - DPCD_ADDR_LANE0_1_STATUS);
-
exynos_dp_get_adjust_train(dp, adjust_request);
buf[0] = DPCD_SCRAMBLING_DISABLED |
--
1.7.9.2.359.gebfc2