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[SRU,J,1/1] drm/panfrost: Fix the error path in panfrost_mmu_map_fault_addr()

Message ID 20240925040110.11539-2-hui.wang@canonical.com
State New
Headers show
Series CVE-2024-35951 | expand

Commit Message

Hui Wang Sept. 25, 2024, 4:01 a.m. UTC 
From: Boris Brezillon <boris.brezillon@collabora.com>

If some the pages or sgt allocation failed, we shouldn't release the
pages ref we got earlier, otherwise we will end up with unbalanced
get/put_pages() calls. We should instead leave everything in place
and let the BO release function deal with extra cleanup when the object
is destroyed, or let the fault handler try again next time it's called.

Fixes: 187d2929206e ("drm/panfrost: Add support for GPU heap allocations")
Cc: <stable@vger.kernel.org>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Co-developed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240105184624.508603-18-dmitry.osipenko@collabora.com
(backported from commit 1fc9af813b25e146d3607669247d0f970f5a87c3)
[hui: This fix commit can't be cleanly applied to J and F due to
missing a prerequisite commit 21aa27ddc582 ("drm/shmem-helper: Switch
to reservation lock"), the prerequisite commit will introduce a
significant change hence here can't introduce it in the J and F. So
I edited the fix commit accordingly, changed "goto err_unlock" to
"goto err_bo".]
CVE-2024-35951
Signed-off-by: Hui Wang <hui.wang@canonical.com>
---
 drivers/gpu/drm/panfrost/panfrost_mmu.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)
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Patch

diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index b5ee076c2841f..79acb28717709 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -465,12 +465,19 @@  static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 	mapping_set_unevictable(mapping);
 
 	for (i = page_offset; i < page_offset + NUM_FAULT_PAGES; i++) {
+		/* Can happen if the last fault only partially filled this
+		 * section of the pages array before failing. In that case
+		 * we skip already filled pages.
+		 */
+		if (pages[i])
+			continue;
+
 		pages[i] = shmem_read_mapping_page(mapping, i);
 		if (IS_ERR(pages[i])) {
 			mutex_unlock(&bo->base.pages_lock);
 			ret = PTR_ERR(pages[i]);
 			pages[i] = NULL;
-			goto err_pages;
+			goto err_bo;
 		}
 	}
 
@@ -480,7 +487,7 @@  static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 	ret = sg_alloc_table_from_pages(sgt, pages + page_offset,
 					NUM_FAULT_PAGES, 0, SZ_2M, GFP_KERNEL);
 	if (ret)
-		goto err_pages;
+		goto err_bo;
 
 	ret = dma_map_sgtable(pfdev->dev, sgt, DMA_BIDIRECTIONAL, 0);
 	if (ret)
@@ -500,8 +507,6 @@  static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 
 err_map:
 	sg_free_table(sgt);
-err_pages:
-	drm_gem_shmem_put_pages(&bo->base);
 err_bo:
 	panfrost_gem_mapping_put(bomapping);
 	return ret;