FAILED: patch "[PATCH] drm/amdgpu: disallow multiple FENCE chunks in one submit" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 931cd1d1baeae68e8eb2c23bc1f3d8934dca6241
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026082049-refocus-deviator-76f3@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 931cd1d1baeae68e8eb2c23bc1f3d8934dca6241 Mon Sep 17 00:00:00 2001
From: Junrui Luo <[email protected]>
Date: Thu, 6 Aug 2026 12:45:24 +0800
Subject: [PATCH] drm/amdgpu: disallow multiple FENCE chunks in one submit
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

amdgpu_cs_pass1() dispatches on chunk_id once per chunk without rejecting repeated ids. p->uf_bo is a single-slot field, so a submission carrying two AMDGPU_CHUNK_ID_FENCE chunks runs amdgpu_cs_p1_user_fence() twice, and the second run overwrites p->uf_bo with a freshly referenced BO without dropping the reference taken by the first.

amdgpu_cs_parser_fini() only unrefs the final p->uf_bo, so every FENCE chunk but the last leaks a BO reference. The leaked BO outlives handle close and process exit.

Reject duplicate FENCE chunks the same way commit fec5f8e8c6bc ("drm/amdgpu: disallow multiple BO_HANDLES chunks in one submit") did for p->bo_list.

index f8bf0f6b5097..6798f6decc37 100644
@@ -248,6 +248,10 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
 			if (size < sizeof(struct drm_amdgpu_cs_chunk_fence))
 				goto free_partial_kdata;
 
+			/* Only a single user fence is allowed to simplify handling. */
+			if (p->uf_bo)
+				goto free_partial_kdata;
+
 			ret = amdgpu_cs_p1_user_fence(p, p->chunks[i].kdata,
 						      &uf_offset);
 			if (ret)

From: Junrui Luo <[email protected]>

[ Upstream commit 931cd1d1baeae68e8eb2c23bc1f3d8934dca6241 ]

amdgpu_cs_pass1() dispatches on chunk_id once per chunk without rejecting repeated ids. p->uf_bo is a single-slot field, so a submission carrying two AMDGPU_CHUNK_ID_FENCE chunks runs amdgpu_cs_p1_user_fence() twice, and the second run overwrites p->uf_bo with a freshly referenced BO without dropping the reference taken by the first.

amdgpu_cs_parser_fini() only unrefs the final p->uf_bo, so every FENCE chunk but the last leaks a BO reference. The leaked BO outlives handle close and process exit.

Reject duplicate FENCE chunks the same way commit fec5f8e8c6bc ("drm/amdgpu: disallow multiple BO_HANDLES chunks in one submit") did for p->bo_list.

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++++
 1 file changed, 4 insertions(+)

index dcf7cd290b889..e9d51002001a4 100644
@@ -247,6 +247,10 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
 			if (size < sizeof(struct drm_amdgpu_cs_chunk_fence))
 				goto free_partial_kdata;
 
+			/* Only a single user fence is allowed to simplify handling. */
+			if (p->uf_entry.tv.bo)
+				goto free_partial_kdata;
+
 			ret = amdgpu_cs_p1_user_fence(p, p->chunks[i].kdata,
 						      &uf_offset);
 			if (ret)

2.53.0