[patch 014/114] mm: vmap fix overflow

[Greg KH]

2.6.28-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Nick Piggin <npiggin@xxxxxxx>

commit 7766970cc13e9071b356b1f2a48a9eb8675bfcce upstream.

The new vmap allocator can wrap the address and get confused in the case
of large allocations or VMALLOC_END near the end of address space.

Problem reported by Christoph Hellwig on a 32-bit XFS workload.

Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Reported-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 mm/vmalloc.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -323,6 +323,7 @@ static struct vmap_area *alloc_vmap_area
 	unsigned long addr;
 	int purged = 0;
 
+	BUG_ON(!size);
 	BUG_ON(size & ~PAGE_MASK);
 
 	va = kmalloc_node(sizeof(struct vmap_area),
@@ -334,6 +335,9 @@ retry:
 	addr = ALIGN(vstart, align);
 
 	spin_lock(&vmap_area_lock);
+	if (addr + size - 1 < addr)
+		goto overflow;
+
 	/* XXX: could have a last_hole cache */
 	n = vmap_area_root.rb_node;
 	if (n) {
@@ -365,6 +369,8 @@ retry:
 
 		while (addr + size > first->va_start && addr + size <= vend) {
 			addr = ALIGN(first->va_end + PAGE_SIZE, align);
+			if (addr + size - 1 < addr)
+				goto overflow;
 
 			n = rb_next(&first->rb_node);
 			if (n)
@@ -375,6 +381,7 @@ retry:
 	}
 found:
 	if (addr + size > vend) {
+overflow:
 		spin_unlock(&vmap_area_lock);
 		if (!purged) {
 			purge_vmap_area_lazy();


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