[PATCH 05/22] mm/hmm: Only set FAULT_FLAG_ALLOW_RETRY for non-blocking

Christoph Hellwig
2019-07-01T06:20:37Z

From: "Kuehling, Felix" <Felix.Kuehling@amd.com>

Don't set this flag by default in hmm_vma_do_fault. It is set
conditionally just a few lines below. Setting it unconditionally can lead
to handle_mm_fault doing a non-blocking fault, returning -EBUSY and
unlocking mmap_sem unexpectedly.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
mm/hmm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hmm.c b/mm/hmm.c
index dce4e70e648a..826816ab2377 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -328,7 +328,7 @@ struct hmm_vma_walk {
static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
bool write_fault, uint64_t *pfn)
{
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
+ unsigned int flags = FAULT_FLAG_REMOTE;
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
struct vm_area_struct *vma = walk->vma;