From 931cd1d1baeae68e8eb2c23bc1f3d8934dca6241 Mon Sep 17 00:00:00 2001 From: Junrui Luo 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=utf8 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. Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)") Reported-by: Yuhao Jiang Assisted-by: Claude:claude-opus-5 Cc: stable@vger.kernel.org Reviewed-by: Christian König Signed-off-by: Junrui Luo Signed-off-by: Alex Deucher (cherry picked from commit 665b1fc2a1845206408f9a2c6da67101789edb82) --- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c index f8bf0f6b5097..6798f6decc37 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -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) -- 2.47.3