The vmap RB tree store the elements in order and no overlap between any of
them. The comparison in __insert_vmap_area() is to decide which direction
the search should follow and make sure the new vmap_area is not overlap
with any other.
Current implementation fails to do the overlap check.
When first "if" is not true, it means
va->va_start >= tmp_va->va_end
And with the truth
xxx->va_end > xxx->va_start
The deduction is
va->va_end > tmp_va->va_start
which is the condition in second "if".
This patch changes a little of the comparison in __insert_vmap_area() to
make sure it forbids the overlapped vmap_area.
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
---
mm/vmalloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 0b057628a7ba..8087451cb332 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -360,9 +360,9 @@ static void __insert_vmap_area(struct vmap_area *va)
parent = *p;
tmp_va = rb_entry(parent, struct vmap_area, rb_node);
- if (va->va_start < tmp_va->va_end)
+ if (va->va_end <= tmp_va->va_start)
p = &(*p)->rb_left;
- else if (va->va_end > tmp_va->va_start)
+ else if (va->va_start >= tmp_va->va_end)
p = &(*p)->rb_right;
else
BUG();
--
2.11.0
--
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