FAILED: patch "[PATCH] drm/amdgpu: fix amdgpu_cs_p1_user_fence" failed to apply to 6.5-stable tree

The patch below does not apply to the 6.5-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-6.5.y
git checkout FETCH_HEAD
git cherry-pick -x 35588314e963938dfdcdb792c9170108399377d6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023091615-wick-punch-6c68@gregkh' --subject-prefix 'PATCH 6.5.y' HEAD^..

Possible dependencies:

35588314e963 ("drm/amdgpu: fix amdgpu_cs_p1_user_fence") ca6c1e210aa7 ("drm/amdgpu: use the new drm_exec object for CS v3") 8abc1eb2987a ("drm/amdkfd: switch over to using drm_exec v3")

thanks,

greg k-h

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

From 35588314e963938dfdcdb792c9170108399377d6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <[email protected]>
Date: Fri, 25 Aug 2023 15:28:00 +0200
Subject: [PATCH] drm/amdgpu: fix amdgpu_cs_p1_user_fence
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The offset is just 32bits here so this can potentially overflow if somebody specifies a large value. Instead reduce the size to calculate the last possible offset.

The error handling path incorrectly drops the reference to the user fence BO resulting in potential reference count underflow.

index 49dd9aa8da70..efdb1c48f431 100644
@@ -127,7 +127,6 @@ static int amdgpu_cs_p1_user_fence(struct amdgpu_cs_parser *p,
 {
 	struct drm_gem_object *gobj;
 	unsigned long size;
-	int r;
 
 	gobj = drm_gem_object_lookup(p->filp, data->handle);
 	if (gobj == NULL)

@@ -137,23 +136,14 @@ static int amdgpu_cs_p1_user_fence(struct amdgpu_cs_parser *p,
 	drm_gem_object_put(gobj);
 
 	size = amdgpu_bo_size(p->uf_bo);
-	if (size != PAGE_SIZE || (data->offset + 8) > size) {
-		r = -EINVAL;
-		goto error_unref;
-	}
+	if (size != PAGE_SIZE || data->offset > (size - 8))
+		return -EINVAL;
 
-	if (amdgpu_ttm_tt_get_usermm(p->uf_bo->tbo.ttm)) {
-		r = -EINVAL;
-		goto error_unref;
-	}
+	if (amdgpu_ttm_tt_get_usermm(p->uf_bo->tbo.ttm))
+		return -EINVAL;
 
 	*offset = data->offset;
-
 	return 0;
-
-error_unref:
-	amdgpu_bo_unref(&p->uf_bo);
-	return r;
 }
 
 static int amdgpu_cs_p1_bo_handles(struct amdgpu_cs_parser *p,