FAILED: patch "[PATCH] drm/amdgpu: Fix vmid_wait fence leak in amdgpu_ring_init()" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x aea841bc62a76242396610d22d8ff40c13065f64
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026092940-transfer-galore-d90b@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From aea841bc62a76242396610d22d8ff40c13065f64 Mon Sep 17 00:00:00 2001
From: Wentao Liang <[email protected]>
Date: Wed, 16 Sep 2026 10:01:39 +0000
Subject: [PATCH] drm/amdgpu: Fix vmid_wait fence leak in amdgpu_ring_init()

amdgpu_ring_init() initializes ring->vmid_wait with a reference to the stub fence taken via dma_fence_get_stub(). When a later step of the initialization fails, e.g. amdgpu_fence_driver_init_ring(), a writeback slot allocation or the ring buffer allocation, the function returns an error without releasing the stub fence reference and the reference is leaked if the ring is torn down without amdgpu_ring_fini().

Move the stub fence assignment to the end of the initialization, right before the ring is registered with the GPU scheduler, where no further failure is possible. The stub fence is only consumed by command submission handling in amdgpu_ids.c once the ring is up and running, so nothing reads it during the error-prone part of the initialization.

index 686c92e96025..5922406d0a03 100644
@@ -254,7 +254,6 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 		ring->adev = adev;
 		ring->num_hw_submission = sched_hw_submission;
 		ring->sched_score = sched_score;
-		ring->vmid_wait = dma_fence_get_stub();
 
 		ring->idx = adev->num_rings++;
 		adev->rings[ring->idx] = ring;

@@ -374,6 +373,7 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 
 	ring->max_dw = max_dw;
 	ring->hw_prio = hw_prio;
+	ring->vmid_wait = dma_fence_get_stub();
 
 	if (!ring->no_scheduler && ring->funcs->type < AMDGPU_HW_IP_NUM) {
 		hw_ip = ring->funcs->type;