mm: vmap fix overflow
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@suse.de>
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 903cad4..ed3705e 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -323,6 +323,7 @@
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 @@
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 @@
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 @@
}
found:
if (addr + size > vend) {
+overflow:
spin_unlock(&vmap_area_lock);
if (!purged) {
purge_vmap_area_lazy();