From: Honglei Huang <honghuan@amd.com>
Date: Wed, 1 Jul 2026 06:28:00 +0000 (+0800)
Subject: drm/gpusvm: publish dpagemap early to avoid device mapping leak on error
X-Git-Tag: v7.2-rc4~13^2~3^2~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7f708f51e3955bda0d77a0b67ab9bea6c97fea99;p=thirdparty%2Fkernel%2Flinux.git

drm/gpusvm: publish dpagemap early to avoid device mapping leak on error

drm_gpusvm_get_pages() only stored the local dpagemap into
svm_pages->dpagemap on the success path. If a later page failed (e.g.
-EOPNOTSUPP when ctx->allow_mixed is false) and jumped to err_unmap,
svm_pages->dpagemap was still NULL, so __drm_gpusvm_unmap_pages() skipped
device_unmap() and leaked the device mappings already created.

Assign svm_pages->dpagemap when the first device page is mapped so the
err_unmap path can device_unmap() those mappings.

This issue was found by Sashiko AI review.

Fixes: f70da6f99d4f ("drm/gpusvm: pull out drm_gpusvm_pages substructure")
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Honglei Huang <honghuan@amd.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260701062800.409248-4-honghuan@amd.com
---

diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
index 44bb19658dd6..9a06ff7d2608 100644
--- a/drivers/gpu/drm/drm_gpusvm.c
+++ b/drivers/gpu/drm/drm_gpusvm.c
@@ -1544,6 +1544,16 @@ map_pages:
 					err = -EAGAIN;
 					goto err_unmap;
 				}
+
+				/*
+				 * Set the dpagemap as soon as the first
+				 * device page is mapped so the err_unmap path
+				 * can device_unmap() the device mappings that
+				 * have already been created.
+				 */
+				drm_pagemap_get(dpagemap);
+				drm_pagemap_put(svm_pages->dpagemap);
+				svm_pages->dpagemap = dpagemap;
 			}
 			svm_pages->dma_addr[j] =
 				dpagemap->ops->device_map(dpagemap,
@@ -1611,12 +1621,8 @@ map_pages:
 			goto err_unmap;
 	}
 
-	if (pagemap) {
+	if (pagemap)
 		flags.has_devmem_pages = true;
-		drm_pagemap_get(dpagemap);
-		drm_pagemap_put(svm_pages->dpagemap);
-		svm_pages->dpagemap = dpagemap;
-	}
 
 	/* WRITE_ONCE pairs with READ_ONCE for opportunistic checks */
 	WRITE_ONCE(svm_pages->flags.__flags, flags.__flags);