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authorLinus Torvalds <torvalds@linux-foundation.org>2022-09-09 07:44:33 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2022-09-09 07:44:33 -0400
commit725f3f3b2708d8f3fe56df8113bfdc7380d52dc9 (patch)
tree9cfe787ece112032ba3be8df9ab24e989f3333aa /drivers/vfio
parent83dfc0e2fd008b6fd2df70f6635cc4def41da056 (diff)
parent873aefb376bbc0ed1dd2381ea1d6ec88106fdbd4 (diff)
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Merge tag 'vfio-v6.0-rc5' of https://github.com/awilliam/linux-vfio
Pull VFIO fix from Alex Williamson: - Fix zero page refcount leak (Alex Williamson) * tag 'vfio-v6.0-rc5' of https://github.com/awilliam/linux-vfio: vfio/type1: Unpin zero pages
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/vfio_iommu_type1.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index db516c90a977..8706482665d1 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -558,6 +558,18 @@ static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM,
pages, NULL, NULL);
if (ret > 0) {
+ int i;
+
+ /*
+ * The zero page is always resident, we don't need to pin it
+ * and it falls into our invalid/reserved test so we don't
+ * unpin in put_pfn(). Unpin all zero pages in the batch here.
+ */
+ for (i = 0 ; i < ret; i++) {
+ if (unlikely(is_zero_pfn(page_to_pfn(pages[i]))))
+ unpin_user_page(pages[i]);
+ }
+
*pfn = page_to_pfn(pages[0]);
goto done;
}