iommu/amd: Fix BUG when faulting a PROT_NONE VMA
handle_mm_fault indirectly triggers a BUG in do_numa_page
when given a VMA without read/write/execute access. Check
this condition in do_fault.
do_fault -> handle_mm_fault -> handle_pte_fault -> do_numa_page
mm/memory.c
3147 static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
....
3159 /* A PROT_NONE fault should not end up here */
3160 BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
Signed-off-by: Jay Cornwall <jay@jcornwall.me>
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 1131664..d21d4ed 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -516,6 +516,13 @@
goto out;
}
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) {
+ /* handle_mm_fault would BUG_ON() */
+ up_read(&mm->mmap_sem);
+ handle_fault_error(fault);
+ goto out;
+ }
+
ret = handle_mm_fault(mm, vma, address, write);
if (ret & VM_FAULT_ERROR) {
/* failed to service fault */