From 7766970cc13e9071b356b1f2a48a9eb8675bfcce Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 27 Feb 2009 14:03:03 -0800 Subject: [PATCH] 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 Reported-by: Christoph Hellwig Cc: [2.6.28.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 903cad46e796..ed3705e4b83f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -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(); -- 2.20.1