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authorTejun Heo <tj@kernel.org>2012-01-13 10:14:12 -0800
committerIngo Molnar <mingo@elte.hu>2012-01-16 08:38:06 +0100
commit5d53cb27d849c899136c048ec84c940ac449494b (patch)
tree66c78c014a06641245fa3cd219afabdc7afdf427 /mm
parentedf7c8148ec40c0fd27c0ef3f688defcc65e3913 (diff)
downloadlinux-5d53cb27d849c899136c048ec84c940ac449494b.tar.gz
memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
7bd0b0f0da ("memblock: Reimplement memblock allocation using reverse free area iterator") implemented a simple top-down allocator using a reverse memblock iterator. To avoid underflow in the allocator loop, it simply raised the lower boundary to the requested size under the assumption that requested size would be far smaller than available memblocks. This causes early page table allocation failure under certain configurations in Xen. Fix it by checking for underflow directly instead of bumping up lower bound. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: rjw@sisk.pl Cc: xen-devel@lists.xensource.com Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120113181412.GA11112@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'mm')
-rw-r--r--mm/memblock.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/memblock.c b/mm/memblock.c
index 2f55f19b7c8..77b5f227e1d 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -106,14 +106,17 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t start,
if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
end = memblock.current_limit;
- /* adjust @start to avoid underflow and allocating the first page */
- start = max3(start, size, (phys_addr_t)PAGE_SIZE);
+ /* avoid allocating the first page */
+ start = max_t(phys_addr_t, start, PAGE_SIZE);
end = max(start, end);
for_each_free_mem_range_reverse(i, nid, &this_start, &this_end, NULL) {
this_start = clamp(this_start, start, end);
this_end = clamp(this_end, start, end);
+ if (this_end < size)
+ continue;
+
cand = round_down(this_end - size, align);
if (cand >= this_start)
return cand;