From: Chris Wright The topdown changes in 2.6.12-rc1 can cause large allocations with large stack limit to fail, despite there being space available. The mmap_base-len is only valid when len >= mmap_base. However, nothing in topdown allocator checks this. It's only (now) caught at higher level, which will cause allocation to simply fail. The following change restores the fallback to bottom-up path, which will allow large allocations with large stack limit to potentially still succeed. Signed-off-by: Chris Wright Signed-off-by: Andrew Morton --- mm/mmap.c | 4 ++++ 1 files changed, 4 insertions(+) diff -puN mm/mmap.c~mmap-topdown-fix-for-large-stack-limit-large-allocation mm/mmap.c --- 25/mm/mmap.c~mmap-topdown-fix-for-large-stack-limit-large-allocation 2005-05-31 02:43:55.000000000 -0700 +++ 25-akpm/mm/mmap.c 2005-05-31 02:43:55.000000000 -0700 @@ -1267,6 +1267,9 @@ arch_get_unmapped_area_topdown(struct fi return (mm->free_area_cache = addr-len); } + if (mm->mmap_base < len) + goto bottomup; + addr = mm->mmap_base-len; do { @@ -1288,6 +1291,7 @@ arch_get_unmapped_area_topdown(struct fi addr = vma->vm_start-len; } while (len < vma->vm_start); +bottomup: /* * A failed mmap() very likely causes application failure, * so fall back to the bottom-up function here. This scenario _