Patch "drm/amd/display: Spinlock before reading event" has been added to the 6.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Spinlock before reading event

to the 6.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-spinlock-before-reading-event.patch
and it can be found in the queue-6.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1344f55ca737d9f655e17550bbf57a27b4019256
Author: Alex Hung <alex.hung@xxxxxxx>
Date:   Fri Apr 26 10:33:47 2024 -0600

    drm/amd/display: Spinlock before reading event
    
    [ 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@xxxxxxx>
    Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx>
    Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
    Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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 c00d96ec8be4..e3662f646baa 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8645,15 +8645,13 @@ 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);
 	}