s390/pci: fix use after free in dma_init

After a failure during registration of the dma_table (because of the
function being in error state) we free its memory but don't reset the
associated pointer to zero.

When we then receive a notification from firmware (about the function
being in error state) we'll try to walk and free the dma_table again.

Fix this by resetting the dma_table pointer. In addition to that make
sure that we free the iommu_bitmap when appropriate.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index e595e89eac65d1f59831b5766d96507fbdbbd75a..1ea8c07eab849e467e5678c7e3dc662c49090860 100644 (file)
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -457,7 +457,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
        zdev->dma_table = dma_alloc_cpu_table();
        if (!zdev->dma_table) {
                rc = -ENOMEM;
-               goto out_clean;
+               goto out;
        }
 
        /*
@@ -477,18 +477,22 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
        zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
        if (!zdev->iommu_bitmap) {
                rc = -ENOMEM;
-               goto out_reg;
+               goto free_dma_table;
        }
 
        rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
                                (u64) zdev->dma_table);
        if (rc)
-               goto out_reg;
-       return 0;
+               goto free_bitmap;
 
-out_reg:
+       return 0;
+free_bitmap:
+       vfree(zdev->iommu_bitmap);
+       zdev->iommu_bitmap = NULL;
+free_dma_table:
        dma_free_cpu_table(zdev->dma_table);
-out_clean:
+       zdev->dma_table = NULL;
+out:
        return rc;
 }