Messages in this thread | | | From | Michael Kelley <> | Subject | RE: [PATCH v4 2/5] swiotlb: Enforce page alignment in swiotlb_alloc() | Date | Wed, 21 Feb 2024 23:36:04 +0000 |
| |
From: Will Deacon <will@kernel.org> Sent: Wednesday, February 21, 2024 3:35 AM > > 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: Christoph Hellwig <hch@lst.de> > Cc: Marek Szyprowski <m.szyprowski@samsung.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Dexuan Cui <decui@microsoft.com> > Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com> > Signed-off-by: Will Deacon <will@kernel.org> > --- > kernel/dma/swiotlb.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 2ec2cc81f1a2..ab7fbb40bc55 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -1643,6 +1643,12 @@ 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)); > } > -- > 2.44.0.rc0.258.g7320e95886-goog
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
| |