From: Will Deacon <will@xxxxxxxxxx>
commit 823353b7cf0ea9dfb09f5181d5fb2825d727200b upstream.
When allocating pages from a restricted DMA pool in swiotlb_alloc(),
the buffer address is blindly converted to a 'struct page *' that is
returned to the caller. In the unlikely event of an allocation bug,
page-unaligned addresses are not detected and slots can silently be
double-allocated.
Add a simple check of the buffer alignment in swiotlb_alloc() to make
debugging a little easier if something has gone wonky.
Cc: stable@xxxxxxxxxxxxxxx # v6.6+
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
Reviewed-by: Petr Tesarik <petr.tesarik1@xxxxxxxxxxxxxxxxxxx>
Tested-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Fabio Estevam <festevam@xxxxxxx>
---
kernel/dma/swiotlb.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index a7d5fb473b32..4c10700c61d2 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1627,6 +1627,12 @@ struct page *swiotlb_alloc(struct device *dev, size_t size)
return NULL;
tlb_addr = slot_addr(pool->start, index);
+ if (unlikely(!PAGE_ALIGNED(tlb_addr))) {
+ dev_WARN_ONCE(dev, 1, "Cannot allocate pages from non page-aligned swiotlb addr 0x%pa.\n",
+ &tlb_addr);
+ swiotlb_release_slots(dev, tlb_addr);
+ return NULL;
+ }
return pfn_to_page(PFN_DOWN(tlb_addr));
}
--
2.34.1
