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mm: vmap fix overflow

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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>
This commit is contained in:
Nick Piggin 2009-02-27 14:03:03 -08:00 committed by Linus Torvalds
parent 5170836679
commit 7766970cc1
1 changed files with 7 additions and 0 deletions
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7
mm/vmalloc.c
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@ -323,6 +323,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
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();