From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Kirill reported that he hit:
>> + if (vma || addr) {
>> + WARN_ON_ONCE(!addr || addr == -1);
>
> Trinity triggered the WARN for me:
This was just a dumb mistake. I put the WARN_ON() in and planned to
have addr=0 mean "use nid". But, I realized pretty quickly that addr=0
_is_ a valid place to fault. So I made it addr=-1 in
__alloc_buddy_huge_page_no_mpol(), but I did not fix up the WARN_ON().
So hitting the warning in this case was harmless. But, fix up the
warning condition.
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
---
b/mm/hugetlb.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff -puN mm/hugetlb.c~hugetlbfs-fix-warn mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlbfs-fix-warn 2015-10-21 14:40:15.809961389 -0700
+++ b/mm/hugetlb.c 2015-10-21 14:40:15.814961616 -0700
@@ -1520,8 +1520,14 @@ static struct page *__alloc_buddy_huge_p
if (hstate_is_gigantic(h))
return NULL;
- if (vma || addr) {
- VM_WARN_ON_ONCE(!addr || addr == -1);
+ /*
+ * Make sure that anyone specifying 'nid' is not also
+ * specifying a VMA. This makes sure the caller is
+ * picking _one_ of the modes with which we can call this
+ * function, not both.
+ */
+ if (vma || (addr != -1)) {
+ VM_WARN_ON_ONCE(addr == -1);
VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
}
/*
_
--
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