Hi Marc,
On 3/3/20 12:51 PM, Marc Zyngier wrote:
> The way cookie_init_hw_msi_region() allocates the iommu_dma_msi_page
> structures doesn't match the way iommu_put_dma_cookie() frees them.
>
> The former performs a single allocation of all the required structures,
> while the latter tries to free them one at a time. It doesn't quite
> work for the main use case (the GICv3 ITS where the range is 64kB)
> when the base ganule size is 4kB.
>
> This leads to a nice slab corruption on teardown, which is easily
> observable by simply creating a VF on a SRIOV-capable device, and
> tearing it down immediately (no need to even make use of it).
>
> Fix it by allocating iommu_dma_msi_page structures one at a time.
>
> Fixes: 7c1b058c8b5a3 ("iommu/dma: Handle IOMMU API reserved regions")
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: Joerg Roedel <jroedel@xxxxxxx>
> Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/iommu/dma-iommu.c | 36 ++++++++++++++++++++++++------------
> 1 file changed, 24 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index a2e96a5fd9a7..01fa64856c12 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -171,25 +171,37 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,
> phys_addr_t start, phys_addr_t end)
> {
> struct iova_domain *iovad = &cookie->iovad;
> - struct iommu_dma_msi_page *msi_page;
> - int i, num_pages;
> + struct iommu_dma_msi_page *msi_page, *tmp;
> + int i, num_pages, ret = 0;
> + phys_addr_t base;
>
> - start -= iova_offset(iovad, start);
> + base = start -= iova_offset(iovad, start);
> num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);
>
> - msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);
> - if (!msi_page)
> - return -ENOMEM;
> -
> for (i = 0; i < num_pages; i++) {
> - msi_page[i].phys = start;
> - msi_page[i].iova = start;
> - INIT_LIST_HEAD(&msi_page[i].list);
> - list_add(&msi_page[i].list, &cookie->msi_page_list);
> + msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL);
> + if (!msi_page) {
> + ret = -ENOMEM;
> + break;
> + }
> + msi_page->phys = start;
> + msi_page->iova = start;
> + INIT_LIST_HEAD(&msi_page->list);
> + list_add(&msi_page->list, &cookie->msi_page_list);
> start += iovad->granule;
> }
>
> - return 0;
> + if (ret) {
> + list_for_each_entry_safe(msi_page, tmp,
> + &cookie->msi_page_list, list) {
> + if (msi_page->phys >= base && msi_page->phys < start) {
> + list_del(&msi_page->list);
> + kfree(msi_page);
> + }
> + }
> + }
> +
> + return ret;
> }
>
> static int iova_reserve_pci_windows(struct pci_dev *dev,
>
