[PATCH] drm/amdgpu: Fixes uninitialized variable usage in amdgpu_dm_setup_replay

[Lakha, Bhawanpreet]

[AMD Official Use Only - General]

Thanks,

Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>

________________________________
From: Yuran Pereira <yuran.pereira at hotmail.com>
Sent: October 26, 2023 5:25 PM
To: airlied at gmail.com <airlied at gmail.com>
Cc: Yuran Pereira <yuran.pereira at hotmail.com>; Wentland, Harry <Harry.Wentland at amd.com>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>; Siqueira, Rodrigo <Rodrigo.Siqueira at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; daniel at ffwll.ch <daniel at ffwll.ch>; Lakha, Bhawanpreet <Bhawanpreet.Lakha at amd.com>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; dri-devel at lists.freedesktop.org <dri-devel at lists.freedesktop.org>; linux-kernel at vger.kernel.org <linux-kernel at vger.kernel.org>; linux-kernel-mentees at lists.linuxfoundation.org <linux-kernel-mentees at lists.linuxfoundation.org>
Subject: [PATCH] drm/amdgpu: Fixes uninitialized variable usage in amdgpu_dm_setup_replay

Since `pr_config` is not initialized after its declaration, the
following operations with `replay_enable_option` may be performed
when `replay_enable_option` is holding junk values which could
possibly lead to undefined behaviour

```
    ...
    pr_config.replay_enable_option |= pr_enable_option_static_screen;
    ...

    if (!pr_config.replay_timing_sync_supported)
        pr_config.replay_enable_option &= ~pr_enable_option_general_ui;
    ...
```

This patch initializes `pr_config` after its declaration to ensure that
it doesn't contain junk data, and prevent any undefined behaviour

Addresses-Coverity-ID: 1544428 ("Uninitialized scalar variable")
Fixes: dede1fea4460 ("drm/amd/display: Add Freesync Panel DM code")
Signed-off-by: Yuran Pereira <yuran.pereira at hotmail.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_replay.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_replay.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_replay.c
index 32d3086c4cb7..40526507f50b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_replay.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_replay.c
@@ -23,6 +23,7 @@
  *
  */

+#include <linux/string.h>
 #include "amdgpu_dm_replay.h"
 #include "dc.h"
 #include "dm_helpers.h"
@@ -74,6 +75,8 @@ bool amdgpu_dm_setup_replay(struct dc_link *link, struct amdgpu_dm_connector *ac
         struct replay_config pr_config;
         union replay_debug_flags *debug_flags = NULL;

+       memset(&pr_config, 0, sizeof(pr_config));
+
         // For eDP, if Replay is supported, return true to skip checks
         if (link->replay_settings.config.replay_supported)
                 return true;
--
2.25.1

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20231027/eeabda9b/attachment-0001.htm>