[PATCH AUTOSEL 6.1 13/61] drm/amd/display: Spinlock before reading event

Sasha Levin
2024-08-01T00:29:05Z

From: Alex Hung <alex.hung@amd.com>

[ Upstream commit ae13c8a5cff92015b9a3eb7cee65ebc75859487f ]

[WHY & HOW]
A read of acrtc_attach->base.state->event was not locked so moving it
inside the spinlock.

This fixes a LOCK_EVASION issue reported by Coverity.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 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 160811ac1fb97..2c6caddf1de34 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8052,15 +8052,13 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
bundle->stream_update.vrr_infopacket =
&acrtc_state->stream->vrr_infopacket;
}
- } else if (cursor_update && acrtc_state->active_planes > 0 &&
- acrtc_attach->base.state->event) {
- drm_crtc_vblank_get(pcrtc);
-
+ } else if (cursor_update && acrtc_state->active_planes > 0) {
spin_lock_irqsave(&pcrtc->dev->event_lock, flags);
-
- acrtc_attach->event = acrtc_attach->base.state->event;
- acrtc_attach->base.state->event = NULL;
-
+ if (acrtc_attach->base.state->event) {
+ drm_crtc_vblank_get(pcrtc);
+ acrtc_attach->event = acrtc_attach->base.state->event;
+ acrtc_attach->base.state->event = NULL;
+ }
spin_unlock_irqrestore(&pcrtc->dev->event_lock, flags);
}

--
2.43.0