linux-kernel - AW: [PATCH] drm/amdgpu/display: Fix an error handling path in 'dm_update_crtc

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Date:   Mon, 9 Mar 2020 08:24:04 +0000
From:   Walter Harms <wharms@....de>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        "harry.wentland@....com" <harry.wentland@....com>,
        "sunpeng.li@....com" <sunpeng.li@....com>,
        "alexander.deucher@....com" <alexander.deucher@....com>,
        "christian.koenig@....com" <christian.koenig@....com>,
        "David1.Zhou@....com" <David1.Zhou@....com>,
        "airlied@...ux.ie" <airlied@...ux.ie>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "nicholas.kazlauskas@....com" <nicholas.kazlauskas@....com>,
        "Bhawanpreet.Lakha@....com" <Bhawanpreet.Lakha@....com>,
        "mario.kleiner.de@...il.com" <mario.kleiner.de@...il.com>,
        "David.Francis@....com" <David.Francis@....com>
CC:     "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: AW: [PATCH] drm/amdgpu/display: Fix an error handling path in
 'dm_update_crtc_state()'

________________________________________
Von: kernel-janitors-owner@...r.kernel.org <kernel-janitors-owner@...r.kernel.org> im Auftrag von Christophe JAILLET <christophe.jaillet@...adoo.fr>
Gesendet: Sonntag, 8. März 2020 10:26
An: harry.wentland@....com; sunpeng.li@....com; alexander.deucher@....com; christian.koenig@....com; David1.Zhou@....com; airlied@...ux.ie; daniel@...ll.ch; nicholas.kazlauskas@....com; Bhawanpreet.Lakha@....com; mario.kleiner.de@...il.com; David.Francis@....com
Cc: amd-gfx@...ts.freedesktop.org; dri-devel@...ts.freedesktop.org; linux-kernel@...r.kernel.org; kernel-janitors@...r.kernel.org; Christophe JAILLET
Betreff: [PATCH] drm/amdgpu/display: Fix an error handling path in 'dm_update_crtc_state()'

'dc_stream_release()' may be called twice. Once here, and once below in the
error handling path if we branch to the 'fail' label.

Set 'new_stream' to NULL, once released to avoid the duplicated release
function call.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
Maybe the 'goto fail' at line 7745 should be turned into a 'return ret'
instead. Could be clearer.

No Fixes tag provided because I've not been able to dig deep enough in the
git history.
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 97c1b01c0fc1..9d7773a77c4f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7704,8 +7704,10 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm,

 skip_modeset:
        /* Release extra reference */
-       if (new_stream)
-                dc_stream_release(new_stream);
+       if (new_stream) {
+               dc_stream_release(new_stream);
+               new_stream = NULL;
+       }

dc_stream_release() is NULL-checked, so the if can be dropped.

re,
 wh

        /*
         * We want to do dc stream updates that do not require a
--
2.20.1