From: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Date: Mon, 23 Feb 2026 12:41:31 +0000 (+0000)
Subject: drm/amdgpu/userq: Do not allow userspace to trivially triger kernel warnings
X-Git-Tag: ceph-for-7.0-rc4~88^2^2~8
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=7b7d7693a55d606d700beb9549c9f7f0e5d9c24f;p=ceph-client.git

drm/amdgpu/userq: Do not allow userspace to trivially triger kernel warnings

Userspace can either deliberately pass in the too small num_fences, or the
required number can legitimately grow between the two calls to the userq
wait ioctl. In both cases we do not want the emit the kernel warning
backtrace since nothing is wrong with the kernel and userspace will simply
get an errno reported back. So lets simply drop the WARN_ONs.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Fixes: a292fdecd728 ("drm/amdgpu: Implement userqueue signal/wait IOCTL")
Cc: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 2c333ea579de6cc20ea7bc50e9595ef72863e65c)
---

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
index 9b9947b94b89..d972dc46f5a8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
@@ -833,7 +833,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 
 			dma_resv_for_each_fence(&resv_cursor, gobj_read[i]->resv,
 						DMA_RESV_USAGE_READ, fence) {
-				if (WARN_ON_ONCE(num_fences >= wait_info->num_fences)) {
+				if (num_fences >= wait_info->num_fences) {
 					r = -EINVAL;
 					goto free_fences;
 				}
@@ -850,7 +850,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 
 			dma_resv_for_each_fence(&resv_cursor, gobj_write[i]->resv,
 						DMA_RESV_USAGE_WRITE, fence) {
-				if (WARN_ON_ONCE(num_fences >= wait_info->num_fences)) {
+				if (num_fences >= wait_info->num_fences) {
 					r = -EINVAL;
 					goto free_fences;
 				}
@@ -874,7 +874,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 					goto free_fences;
 
 				dma_fence_unwrap_for_each(f, &iter, fence) {
-					if (WARN_ON_ONCE(num_fences >= wait_info->num_fences)) {
+					if (num_fences >= wait_info->num_fences) {
 						r = -EINVAL;
 						dma_fence_put(fence);
 						goto free_fences;
@@ -899,7 +899,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 			if (r)
 				goto free_fences;
 
-			if (WARN_ON_ONCE(num_fences >= wait_info->num_fences)) {
+			if (num_fences >= wait_info->num_fences) {
 				r = -EINVAL;
 				dma_fence_put(fence);
 				goto free_fences;