From 73219d178051691a56d57184d8c7f6d0cbe3c5c1 Mon Sep 17 00:00:00 2001 From: Chris Wright Date: Tue, 21 Jun 2005 17:14:52 -0700 Subject: [PATCH] mmap topdown fix for large stack limit, large allocation 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 Signed-off-by: Linus Torvalds --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'mm') diff --git a/mm/mmap.c b/mm/mmap.c index 9da23c1ef9d..da3fa90a0aa 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1267,6 +1267,9 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 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 file *filp, const unsigned long addr0, 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 -- cgit v1.2.3-70-g09d2