[patch 014/114] mm: vmap fix overflow

Greg KH
2009-03-14T01:25:14Z

[-- Attachment #1: mm-vmap-fix-overflow.patch --]
[-- Type: text/plain, Size: 1592 bytes --]

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

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

From: Nick Piggin <npiggin@suse.de>

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@suse.de>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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();