KVM: Fix a race condition for usage of is_hwpoison_address()

is_hwpoison_address accesses the page table, so the caller must hold
current->mm->mmap_sem in read mode. So fix its usage in hva_to_pfn of
kvm accordingly.

Comment is_hwpoison_address to remind other users.

Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 378b0f61fd3..6b44e52caca 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1298,6 +1298,9 @@ done:
 	return ret;
 }
 
+/*
+ * The caller must hold current->mm->mmap_sem in read mode.
+ */
 int is_hwpoison_address(unsigned long addr)
 {
 	pgd_t *pgdp;